# What is CVE-2018-5391? > CVE-2018-5391 is a high-severity flaw (CVSS 7.5) in Linux kernel, published on 6 September 2018. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 32%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2018-5391 ## At a glance - **Verdict:** Fix this soon. Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month. - **Precursor Intelligence risk score:** 49 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes. - **Severity:** High (CVSS 7.5 out of 10) - **Known to be exploited:** No, not on the list of flaws known to be exploited today - **Chance of use in the next 30 days:** 32% (latest exploit-likelihood forecast) - **Published:** 6 September 2018 - **Record last updated:** 7 November 2023 - **Main product:** Linux kernel - **Affected products:** 73 ## What is CVE-2018-5391? In plain terms It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can take it offline. ### The official description The Linux kernel, versions 3.9+, is vulnerable to a denial of service attack with low rates of specially modified packets targeting IP fragment re-assembly. An attacker may cause a denial of service condition by sending specially crafted IP fragments. Various vulnerabilities in IP fragmentation have been discovered and fixed over the years. The current vulnerability (CVE-2018-5391) became exploitable in the Linux kernel with the increase of the IP fragment reassembly queue size. ### What kind of flaw is it? - CWE-20: Improper Input Validation - CWE-400: Uncontrolled Resource Consumption ### How an attack on it works - Where an attacker can be: Anywhere on the internet - How hard it is to pull off: Easy: no special conditions - Login needed first: No login needed - Does someone have to click: No, nobody has to do anything - What an attacker gets: Can take it offline Severity vector: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H` ## Is CVE-2018-5391 being exploited? Not that we know of It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 32%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 32%, 32%, 32%, 32%, 32%, 32%, 32%. ### Timeline - 6 September 2018: Published - 7 November 2023: Record last updated - 19 November 2025: Exploit likelihood jumped - 22 November 2025: Exploit likelihood fell ### How Precursor Intelligence ranks it CVE-2018-5391 scores **49 out of 100 (Medium)**, with the action "Plan remediation". Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less: - Evidence it is being exploited: biggest factor - How severe it is: strong factor - How widely exposed it is: smaller factor - Threat activity around it: smaller factor 85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it. ## Who is affected by CVE-2018-5391? The published record lists 73 products. Versions are as published: "11.5.1 to before 11.6.5.1" means from 11.5.1 up to, but not including, 11.6.5.1. - [Linux kernel](https://www.precursorintelligence.com/product/linux/linux_kernel) by [Linux](https://www.precursorintelligence.com/vendors/linux) (Operating system): 3.9 to 4.18 - [Enterprise Linux Server Aus](https://www.precursorintelligence.com/product/redhat/enterprise_linux_server_aus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 6.4, 6.5, 6.6, 7.2, 7.3, 7.4 - [Big-IP Access Policy Manager](https://www.precursorintelligence.com/product/f5/big-ip_access_policy_manager) by [F5](https://www.precursorintelligence.com/vendors/f5) (Application): 11.5.1 to before 11.6.5.1, 12.1.0 to before 12.1.5, 13.0.0 to before 13.1.3, 14.0.0 to before 14.0.1.1, 14.1.0 to before 14.1.2.4 - [Big-IP Advanced Firewall Manager](https://www.precursorintelligence.com/product/f5/big-ip_advanced_firewall_manager) by [F5](https://www.precursorintelligence.com/vendors/f5) (Application): 11.5.1 to before 11.6.5.1, 12.1.0 to before 12.1.5, 13.0.0 to before 13.1.3, 14.0.0 to before 14.0.1.1, 14.1.0 to before 14.1.2.4 - [Big-IP Analytics](https://www.precursorintelligence.com/product/f5/big-ip_analytics) by [F5](https://www.precursorintelligence.com/vendors/f5) (Application): 11.5.1 to before 11.6.5.1, 12.1.0 to before 12.1.5, 13.0.0 to before 13.1.3, 14.0.0 to before 14.0.1.1, 14.1.0 to before 14.1.2.4 - [Big-IP Application Acceleration Manager](https://www.precursorintelligence.com/product/f5/big-ip_application_acceleration_manager) by [F5](https://www.precursorintelligence.com/vendors/f5) (Application): 11.5.1 to before 11.6.5.1, 12.1.0 to before 12.1.5, 13.0.0 to before 13.1.3, 14.0.0 to before 14.0.1.1, 14.1.0 to before 14.1.2.4 - [Big-IP Application Security Manager](https://www.precursorintelligence.com/product/f5/big-ip_application_security_manager) by [F5](https://www.precursorintelligence.com/vendors/f5) (Application): 11.5.1 to before 11.6.5.1, 12.1.0 to before 12.1.5, 13.0.0 to before 13.1.3, 14.0.0 to before 14.0.1.1, 14.1.0 to before 14.1.2.4 - [Big-IP Domain Name System](https://www.precursorintelligence.com/product/f5/big-ip_domain_name_system) by [F5](https://www.precursorintelligence.com/vendors/f5) (Application): 11.5.1 to before 11.6.5.1, 12.1.0 to before 12.1.5, 13.0.0 to before 13.1.3, 14.0.0 to before 14.0.1.1, 14.1.0 to before 14.1.2.4 - [Big-IP Edge Gateway](https://www.precursorintelligence.com/product/f5/big-ip_edge_gateway) by [F5](https://www.precursorintelligence.com/vendors/f5) (Application): 11.5.1 to before 11.6.5.1, 12.1.0 to before 12.1.5, 13.0.0 to before 13.1.3, 14.0.0 to before 14.0.1.1, 14.1.0 to before 14.1.2.4 - [Big-IP Fraud Protection Service](https://www.precursorintelligence.com/product/f5/big-ip_fraud_protection_service) by [F5](https://www.precursorintelligence.com/vendors/f5) (Application): 11.5.1 to before 11.6.5.1, 12.1.0 to before 12.1.5, 13.0.0 to before 13.1.3, 14.0.0 to before 14.0.1.1, 14.1.0 to before 14.1.2.4 - [Big-IP Global Traffic Manager](https://www.precursorintelligence.com/product/f5/big-ip_global_traffic_manager) by [F5](https://www.precursorintelligence.com/vendors/f5) (Application): 11.5.1 to before 11.6.5.1, 12.1.0 to before 12.1.5, 13.0.0 to before 13.1.3, 14.0.0 to before 14.0.1.1, 14.1.0 to before 14.1.2.4 - [Big-IP Link Controller](https://www.precursorintelligence.com/product/f5/big-ip_link_controller) by [F5](https://www.precursorintelligence.com/vendors/f5) (Application): 11.5.1 to before 11.6.5.1, 12.1.0 to before 12.1.5, 13.0.0 to before 13.1.3, 14.0.0 to before 14.0.1.1, 14.1.0 to before 14.1.2.4 - [Big-IP Local Traffic Manager](https://www.precursorintelligence.com/product/f5/big-ip_local_traffic_manager) by [F5](https://www.precursorintelligence.com/vendors/f5) (Application): 11.5.1 to before 11.6.5.1, 12.1.0 to before 12.1.5, 13.0.0 to before 13.1.3, 14.0.0 to before 14.0.1.1, 14.1.0 to before 14.1.2.4 - [Big-IP Policy Enforcement Manager](https://www.precursorintelligence.com/product/f5/big-ip_policy_enforcement_manager) by [F5](https://www.precursorintelligence.com/vendors/f5) (Application): 11.5.1 to before 11.6.5.1, 12.1.0 to before 12.1.5, 13.0.0 to before 13.1.3, 14.0.0 to before 14.0.1.1, 14.1.0 to before 14.1.2.4 - [Big-IP Webaccelerator](https://www.precursorintelligence.com/product/f5/big-ip_webaccelerator) by [F5](https://www.precursorintelligence.com/vendors/f5) (Application): 11.5.1 to before 11.6.5.1, 12.1.0 to before 12.1.5, 13.0.0 to before 13.1.3, 14.0.0 to before 14.0.1.1, 14.1.0 to before 14.1.2.4 - [Enterprise Linux Server Eus](https://www.precursorintelligence.com/product/redhat/enterprise_linux_server_eus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 6.7, 7.3, 7.4, 7.5 - [Enterprise Linux Server Tus](https://www.precursorintelligence.com/product/redhat/enterprise_linux_server_tus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 6.6, 7.2, 7.3, 7.4 - [Ubuntu Linux](https://www.precursorintelligence.com/product/canonical/ubuntu_linux) by [Canonical](https://www.precursorintelligence.com/vendors/canonical) (Operating system): 12.04, 14.04, 16.04, 18.04 - [Windows 10](https://www.precursorintelligence.com/product/microsoft/windows_10) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): 1607, 1703, 1709, 1803 - [Debian Linux](https://www.precursorintelligence.com/product/debian/debian_linux) by [Debian](https://www.precursorintelligence.com/vendors/debian) (Operating system): 8.0, 9.0 - [Enterprise Linux Desktop](https://www.precursorintelligence.com/product/redhat/enterprise_linux_desktop) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 6.0, 7.0 - [Enterprise Linux Server](https://www.precursorintelligence.com/product/redhat/enterprise_linux_server) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 6.0, 7.0 - [Enterprise Linux Workstation](https://www.precursorintelligence.com/product/redhat/enterprise_linux_workstation) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 6.0, 7.0 - [Windows Server 2016](https://www.precursorintelligence.com/product/microsoft/windows_server_2016) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): 1709, 1803 - [Ruggedcom Rm1224](https://www.precursorintelligence.com/product/siemens/ruggedcom_rm1224) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Ruggedcom Rm1224 Firmware](https://www.precursorintelligence.com/product/siemens/ruggedcom_rm1224_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 6.1 - [Ruggedcom Rox Ii](https://www.precursorintelligence.com/product/siemens/ruggedcom_rox_ii) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Ruggedcom Rox Ii Firmware](https://www.precursorintelligence.com/product/siemens/ruggedcom_rox_ii_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 2.13.3 - [Scalance M-800](https://www.precursorintelligence.com/product/siemens/scalance_m-800) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Scalance M-800 Firmware](https://www.precursorintelligence.com/product/siemens/scalance_m-800_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 6.1 - [Scalance S615](https://www.precursorintelligence.com/product/siemens/scalance_s615) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Scalance S615 Firmware](https://www.precursorintelligence.com/product/siemens/scalance_s615_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 6.1 - [Scalance Sc-600](https://www.precursorintelligence.com/product/siemens/scalance_sc-600) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Scalance Sc-600 Firmware](https://www.precursorintelligence.com/product/siemens/scalance_sc-600_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 2.0 - [Scalance W1700 Ieee 802.11ac](https://www.precursorintelligence.com/product/siemens/scalance_w1700_ieee_802.11ac) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Scalance W1700 Ieee 802.11ac Firmware](https://www.precursorintelligence.com/product/siemens/scalance_w1700_ieee_802.11ac_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 2.0 - Scalance W700 Ieee 802.11a/b/g/n by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - Scalance W700 Ieee 802.11a/b/g/n Firmware by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 6.4 - [Simatic Net Cp 1242-7](https://www.precursorintelligence.com/product/siemens/simatic_net_cp_1242-7) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic Net Cp 1242-7 Firmware](https://www.precursorintelligence.com/product/siemens/simatic_net_cp_1242-7_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 3.2 - [Simatic Net Cp 1243-1](https://www.precursorintelligence.com/product/siemens/simatic_net_cp_1243-1) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic Net Cp 1243-1 Firmware](https://www.precursorintelligence.com/product/siemens/simatic_net_cp_1243-1_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 3.2 - [Simatic Net Cp 1243-7 Lte Eu](https://www.precursorintelligence.com/product/siemens/simatic_net_cp_1243-7_lte_eu) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic Net Cp 1243-7 Lte Eu Firmware](https://www.precursorintelligence.com/product/siemens/simatic_net_cp_1243-7_lte_eu_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 3.2 - [Simatic Net Cp 1243-7 Lte Us](https://www.precursorintelligence.com/product/siemens/simatic_net_cp_1243-7_lte_us) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic Net Cp 1243-7 Lte Us Firmware](https://www.precursorintelligence.com/product/siemens/simatic_net_cp_1243-7_lte_us_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 3.2 - [Simatic Net Cp 1243-8 Irc](https://www.precursorintelligence.com/product/siemens/simatic_net_cp_1243-8_irc) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic Net Cp 1243-8 Irc Firmware](https://www.precursorintelligence.com/product/siemens/simatic_net_cp_1243-8_irc_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 3.2 - [Simatic Net Cp 1542sp-1](https://www.precursorintelligence.com/product/siemens/simatic_net_cp_1542sp-1) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic Net Cp 1542sp-1 Firmware](https://www.precursorintelligence.com/product/siemens/simatic_net_cp_1542sp-1_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 2.1 - [Simatic Net Cp 1542sp-1 Irc](https://www.precursorintelligence.com/product/siemens/simatic_net_cp_1542sp-1_irc) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic Net Cp 1542sp-1 Irc Firmware](https://www.precursorintelligence.com/product/siemens/simatic_net_cp_1542sp-1_irc_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 2.1 - [Simatic Net Cp 1543-1](https://www.precursorintelligence.com/product/siemens/simatic_net_cp_1543-1) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic Net Cp 1543-1 Firmware](https://www.precursorintelligence.com/product/siemens/simatic_net_cp_1543-1_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 2.2 - [Simatic Net Cp 1543sp-1](https://www.precursorintelligence.com/product/siemens/simatic_net_cp_1543sp-1) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic Net Cp 1543sp-1 Firmware](https://www.precursorintelligence.com/product/siemens/simatic_net_cp_1543sp-1_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 2.1 - [Simatic Rf185c](https://www.precursorintelligence.com/product/siemens/simatic_rf185c) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic Rf185c Firmware](https://www.precursorintelligence.com/product/siemens/simatic_rf185c_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 1.3 - [Simatic Rf186c](https://www.precursorintelligence.com/product/siemens/simatic_rf186c) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic Rf186c Firmware](https://www.precursorintelligence.com/product/siemens/simatic_rf186c_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 1.3 - [Simatic Rf186ci](https://www.precursorintelligence.com/product/siemens/simatic_rf186ci) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic Rf186ci Firmware](https://www.precursorintelligence.com/product/siemens/simatic_rf186ci_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 1.3 - [Simatic Rf188](https://www.precursorintelligence.com/product/siemens/simatic_rf188) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic Rf188 Firmware](https://www.precursorintelligence.com/product/siemens/simatic_rf188_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 1.3 - [Simatic Rf188ci](https://www.precursorintelligence.com/product/siemens/simatic_rf188ci) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Simatic Rf188ci Firmware](https://www.precursorintelligence.com/product/siemens/simatic_rf188ci_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 1.3 - [Sinema Remote Connect Server](https://www.precursorintelligence.com/product/siemens/sinema_remote_connect_server) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Hardware): version not specified - [Sinema Remote Connect Server Firmware](https://www.precursorintelligence.com/product/siemens/sinema_remote_connect_server_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): 1.1 to before 2.0.1 - [Windows 7](https://www.precursorintelligence.com/product/microsoft/windows_7) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): version not specified - [Windows 8.1](https://www.precursorintelligence.com/product/microsoft/windows_8.1) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): version not specified - [Windows Rt 8.1](https://www.precursorintelligence.com/product/microsoft/windows_rt_8.1) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): version not specified - [Windows Server 2008](https://www.precursorintelligence.com/product/microsoft/windows_server_2008) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): r2-sp1 - [Windows Server 2012](https://www.precursorintelligence.com/product/microsoft/windows_server_2012) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Operating system): r2 ## How do I fix CVE-2018-5391? 1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list. 2. **Apply the vendor’s fix.** Install the update named in the vendor’s advisory. We’ve put the advisories and patch notes first in the list. 3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in. 4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood. ### References - [git.kernel.org](https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git/commit/?id=c30f1fc041b74ecdb072dd44f858750414b8b19f) (Patch, Vendor advisory) - [lists.debian.org](https://lists.debian.org/debian-lts-announce/2018/08/msg00014.html) (Mitigation, Mailing list, Third-party advisory) - [debian.org](https://www.debian.org/security/2018/dsa-4272) (Mitigation, Third-party advisory) - [arubanetworks.com](http://www.arubanetworks.com/assets/alert/ARUBA-PSA-2018-004.txt) (Third-party advisory) - [huawei.com](http://www.huawei.com/en/psirt/security-advisories/huawei-sa-20200115-01-linux-en) (Broken link) - [openwall.com](http://www.openwall.com/lists/oss-security/2019/06/28/2) (Mailing list, Third-party advisory) - [openwall.com](http://www.openwall.com/lists/oss-security/2019/07/06/3) (Mailing list, Third-party advisory) - [openwall.com](http://www.openwall.com/lists/oss-security/2019/07/06/4) (Mailing list, Third-party advisory) - [securityfocus.com](http://www.securityfocus.com/bid/105108) (Third-party advisory, Vulnerability database) - [securitytracker.com](http://www.securitytracker.com/id/1041476) (Third-party advisory, Vulnerability database) - [securitytracker.com](http://www.securitytracker.com/id/1041637) (Third-party advisory, Vulnerability database) - [access.redhat.com](https://access.redhat.com/errata/RHSA-2018:2785) (Third-party advisory) - [access.redhat.com](https://access.redhat.com/errata/RHSA-2018:2791) (Third-party advisory) - [access.redhat.com](https://access.redhat.com/errata/RHSA-2018:2846) (Third-party advisory) - [access.redhat.com](https://access.redhat.com/errata/RHSA-2018:2924) (Third-party advisory) - [access.redhat.com](https://access.redhat.com/errata/RHSA-2018:2925) (Third-party advisory) - [access.redhat.com](https://access.redhat.com/errata/RHSA-2018:2933) (Third-party advisory) - [access.redhat.com](https://access.redhat.com/errata/RHSA-2018:2948) (Third-party advisory) - [access.redhat.com](https://access.redhat.com/errata/RHSA-2018:3083) (Third-party advisory) - [access.redhat.com](https://access.redhat.com/errata/RHSA-2018:3096) (Third-party advisory) - [access.redhat.com](https://access.redhat.com/errata/RHSA-2018:3459) (Third-party advisory) - [access.redhat.com](https://access.redhat.com/errata/RHSA-2018:3540) (Third-party advisory) - [access.redhat.com](https://access.redhat.com/errata/RHSA-2018:3586) (Third-party advisory) - [access.redhat.com](https://access.redhat.com/errata/RHSA-2018:3590) (Third-party advisory) - [cert-portal.siemens.com](https://cert-portal.siemens.com/productcert/pdf/ssa-377115.pdf) (Third-party advisory) - [lists.debian.org](https://lists.debian.org/debian-lts-announce/2019/03/msg00017.html) (Mailing list, Third-party advisory) - [security.netapp.com](https://security.netapp.com/advisory/ntap-20181003-0002/) (Third-party advisory) - [support.f5.com](https://support.f5.com/csp/article/K74374841?utm_source=f5support&%3Butm_medium=RSS) - [usn.ubuntu.com](https://usn.ubuntu.com/3740-1/) (Third-party advisory) - [usn.ubuntu.com](https://usn.ubuntu.com/3740-2/) (Third-party advisory) - [usn.ubuntu.com](https://usn.ubuntu.com/3741-1/) (Third-party advisory) - [usn.ubuntu.com](https://usn.ubuntu.com/3741-2/) (Third-party advisory) - [usn.ubuntu.com](https://usn.ubuntu.com/3742-1/) (Third-party advisory) - [usn.ubuntu.com](https://usn.ubuntu.com/3742-2/) (Third-party advisory) - [kb.cert.org](https://www.kb.cert.org/vuls/id/641765) (Third-party advisory, Government resource) ## Questions ### What is CVE-2018-5391? CVE-2018-5391 is a high-severity flaw in Linux kernel, published on 6 September 2018. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can take it offline. ### How serious is CVE-2018-5391? It scores 7.5 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2018-5391 is 49 out of 100, which is Medium. Its action is "Plan remediation". Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month. ### Is CVE-2018-5391 being exploited? It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 32%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2018-5391 affect? For Linux kernel: 3.9 to 4.18. The record lists 73 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2018-5391? Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet. ## Does CVE-2018-5391 affect you? Precursor Intelligence keeps checking for you: - **Tell us what you run.** Pick your software from a list, or let us work it out from your website. - **We match it to every flaw.** Over 400,000 published flaws, checked against your list. - **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it. - **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools. Start free (no card, nothing to install): https://www.precursorintelligence.com/register Book a demo: https://www.precursorintelligence.com/contact