# What is CVE-2023-4527? > CVE-2023-4527 is a medium-severity flaw (CVSS 6.5) in Glibc from Gnu, published on 18 September 2023. 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 1.7%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2023-4527 ## At a glance - **Verdict:** Plan it in. No sign of exploitation and a low forecast. Patch it in your normal update cycle. - **Precursor Intelligence risk score:** 44 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes. - **Severity:** Medium (CVSS 6.5 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:** 1.7% (latest exploit-likelihood forecast) - **Published:** 18 September 2023 - **Record last updated:** 16 September 2024 - **Main product:** Glibc from Gnu - **Affected products:** 32 ## What is CVE-2023-4527? 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 A flaw was found in glibc. When the getaddrinfo function is called with the AF_UNSPEC address family and the system is configured with no-aaaa mode via /etc/resolv.conf, a DNS response via TCP larger than 2048 bytes can potentially disclose stack contents through the function returned address data, and may cause a crash. ### What kind of flaw is it? - CWE-125: Out-of-bounds Read - CWE-121: Stack-based Buffer Overflow ### How an attack on it works - Where an attacker can be: Anywhere on the internet - How hard it is to pull off: Hard: conditions must line up - 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:H/PR:N/UI:N/S:U/C:L/I:N/A:H` ## Is CVE-2023-4527 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 1.7%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 1.7%, 1.7%, 1.7%, 1.7%, 1.7%, 1.7%, 1.7%. ### Timeline - 18 September 2023: Published - 16 September 2024: Record last updated ### How Precursor Intelligence ranks it CVE-2023-4527 scores **44 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-2023-4527? The published record lists 32 products. Versions are as published: "before 2.39" means every version up to, but not including, 2.39. - [Glibc](https://www.precursorintelligence.com/product/gnu/glibc) by [Gnu](https://www.precursorintelligence.com/vendors/gnu) (Application): before 2.39 - [Fedora](https://www.precursorintelligence.com/product/fedoraproject/fedora) by [Fedoraproject](https://www.precursorintelligence.com/vendors/fedoraproject) (Operating system): 37, 38, 39 - [Enterprise Linux](https://www.precursorintelligence.com/product/redhat/enterprise_linux) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 8.0, 9.0 - [Enterprise Linux Eus](https://www.precursorintelligence.com/product/redhat/enterprise_linux_eus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 8.8, 9.2 - [Enterprise Linux for Power Little Endian](https://www.precursorintelligence.com/product/redhat/enterprise_linux_for_power_little_endian) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 8.0_ppc64le, 9.2_ppc64le - [Enterprise Linux for Power Little Endian Eus](https://www.precursorintelligence.com/product/redhat/enterprise_linux_for_power_little_endian_eus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 8.8_ppc64le, 9.2_ppc64le - [Codeready Linux Builder Eus](https://www.precursorintelligence.com/product/redhat/codeready_linux_builder_eus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Application): 9.2 - [Codeready Linux Builder Eus for Power Little Endian](https://www.precursorintelligence.com/product/redhat/codeready_linux_builder_eus_for_power_little_endian) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Application): 9.0_ppc64le - [Codeready Linux Builder Eus for Power Little Endian Eus](https://www.precursorintelligence.com/product/redhat/codeready_linux_builder_eus_for_power_little_endian_eus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Application): 9.2_ppc64le - [Codeready Linux Builder for Arm64](https://www.precursorintelligence.com/product/redhat/codeready_linux_builder_for_arm64) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Application): 9.0_aarch64 - [Codeready Linux Builder for Arm64 Eus](https://www.precursorintelligence.com/product/redhat/codeready_linux_builder_for_arm64_eus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Application): 9.2_aarch64 - [Codeready Linux Builder for Ibm Z Systems](https://www.precursorintelligence.com/product/redhat/codeready_linux_builder_for_ibm_z_systems) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Application): 9.0_s390x - [Codeready Linux Builder for Ibm Z Systems Eus](https://www.precursorintelligence.com/product/redhat/codeready_linux_builder_for_ibm_z_systems_eus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Application): 9.2_s390x - [Enterprise Linux for Arm 64](https://www.precursorintelligence.com/product/redhat/enterprise_linux_for_arm_64) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 9.0_aarch64 - [Enterprise Linux for Arm 64 Eus](https://www.precursorintelligence.com/product/redhat/enterprise_linux_for_arm_64_eus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 9.2_aarch64 - [Enterprise Linux for Ibm Z Systems](https://www.precursorintelligence.com/product/redhat/enterprise_linux_for_ibm_z_systems) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 8.0_s390x - [Enterprise Linux for Ibm Z Systems Eus](https://www.precursorintelligence.com/product/redhat/enterprise_linux_for_ibm_z_systems_eus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 8.8_s390x - [Enterprise Linux for Ibm Z Systems Eus S390x](https://www.precursorintelligence.com/product/redhat/enterprise_linux_for_ibm_z_systems_eus_s390x) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 9.2 - [Enterprise Linux for Ibm Z Systems S390x](https://www.precursorintelligence.com/product/redhat/enterprise_linux_for_ibm_z_systems_s390x) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 9.2 - [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): 9.2 - [Enterprise Linux Server for Power Little Endian Update Services for Sap Solutions](https://www.precursorintelligence.com/product/redhat/enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 9.2_ppc64le - [Enterprise Linux Tus](https://www.precursorintelligence.com/product/redhat/enterprise_linux_tus) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 8.8 - [H300s](https://www.precursorintelligence.com/product/netapp/h300s) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Hardware): version not specified - [H300s Firmware](https://www.precursorintelligence.com/product/netapp/h300s_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified - [H410c](https://www.precursorintelligence.com/product/netapp/h410c) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Hardware): version not specified - [H410c Firmware](https://www.precursorintelligence.com/product/netapp/h410c_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified - [H410s](https://www.precursorintelligence.com/product/netapp/h410s) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Hardware): version not specified - [H410s Firmware](https://www.precursorintelligence.com/product/netapp/h410s_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified - [H500s](https://www.precursorintelligence.com/product/netapp/h500s) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Hardware): version not specified - [H500s Firmware](https://www.precursorintelligence.com/product/netapp/h500s_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified - [H700s](https://www.precursorintelligence.com/product/netapp/h700s) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Hardware): version not specified - [H700s Firmware](https://www.precursorintelligence.com/product/netapp/h700s_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified ## How do I fix CVE-2023-4527? 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 latest update from the vendor. The references list where the vendor has published details. 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 - [access.redhat.com](https://access.redhat.com/errata/RHSA-2023:5453) (Third-party advisory) - [access.redhat.com](https://access.redhat.com/errata/RHSA-2023:5455) (Third-party advisory) - [access.redhat.com](https://access.redhat.com/security/cve/CVE-2023-4527) (Third-party advisory) - [bugzilla.redhat.com](https://bugzilla.redhat.com/show_bug.cgi?id=2234712) (Exploit, Issue tracking, Third-party advisory) ## Questions ### What is CVE-2023-4527? CVE-2023-4527 is a medium-severity flaw in Glibc from Gnu, published on 18 September 2023. 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-2023-4527? It scores 6.5 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2023-4527 is 44 out of 100, which is Medium. Its action is "Plan remediation". No sign of exploitation and a low forecast. Patch it in your normal update cycle. ### Is CVE-2023-4527 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 1.7%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2023-4527 affect? For Glibc from Gnu: before 2.39. The record lists 32 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2023-4527? Install the update the vendor names in its advisory. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet. ## Does CVE-2023-4527 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