# What is CVE-2019-12646? > CVE-2019-12646 is a high-severity flaw (CVSS 7.5) in IOS XE from Cisco, published on 25 September 2019. 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 2.0%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2019-12646 ## 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:** 47 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:** 2.0% (latest exploit-likelihood forecast) - **Published:** 25 September 2019 - **Record last updated:** 22 May 2023 - **Main product:** IOS XE from Cisco - **Affected products:** 13 ## What is CVE-2019-12646? 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 vulnerability in the Network Address Translation (NAT) Session Initiation Protocol (SIP) Application Layer Gateway (ALG) of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to improper processing of transient SIP packets on which NAT is performed on an affected device. An attacker could exploit this vulnerability by using UDP port 5060 to send crafted SIP packets through an affected device that is performing NAT for SIP packets. A successful exploit could allow an attacker to cause the device to reload, resulting in a denial of service (DoS) condition. ### What kind of flaw is it? - CWE-665: Improper Initialization ### 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-2019-12646 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 2.0%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 2.0%, 2.0%, 2.0%, 2.0%, 2.0%, 2.0%, 2.0%. ### Timeline - 25 September 2019: Published - 22 May 2023: Record last updated ### How Precursor Intelligence ranks it CVE-2019-12646 scores **47 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-2019-12646? The published record lists 13 products. - [IOS XE](https://www.precursorintelligence.com/product/cisco/ios_xe) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Operating system): 15.4(3)s, 15.5(3)s, 15.6(1)s, 16.3.1, 16.4.1, 16.5.1, 16.6.1, 16.7.1, 16.8.1, 16.9.1, 16.10.1, 16.11.1, 16.12.1 - [1100-4p](https://www.precursorintelligence.com/product/cisco/1100-4p) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [1100-8p](https://www.precursorintelligence.com/product/cisco/1100-8p) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [1101-4p](https://www.precursorintelligence.com/product/cisco/1101-4p) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [1109-2p](https://www.precursorintelligence.com/product/cisco/1109-2p) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [1109-4p](https://www.precursorintelligence.com/product/cisco/1109-4p) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [1111x-8p](https://www.precursorintelligence.com/product/cisco/1111x-8p) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [4221 Integrated Services Router](https://www.precursorintelligence.com/product/cisco/4221_integrated_services_router) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [4331 Integrated Services Router](https://www.precursorintelligence.com/product/cisco/4331_integrated_services_router) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Csr 1000v](https://www.precursorintelligence.com/product/cisco/csr_1000v) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Encs 5100](https://www.precursorintelligence.com/product/cisco/encs_5100) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Encs 5400](https://www.precursorintelligence.com/product/cisco/encs_5400) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Isrv](https://www.precursorintelligence.com/product/cisco/isrv) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified ## How do I fix CVE-2019-12646? 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 advisory 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 - [tools.cisco.com](https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190925-sip-alg) (Vendor advisory) ## Questions ### What is CVE-2019-12646? CVE-2019-12646 is a high-severity flaw in IOS XE from Cisco, published on 25 September 2019. 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-2019-12646? It scores 7.5 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2019-12646 is 47 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-2019-12646 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 2.0%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2019-12646 affect? For IOS XE from Cisco: 15.4(3)s, 15.5(3)s, 15.6(1)s, 16.3.1, 16.4.1, 16.5.1 and 7 more. The record lists 13 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2019-12646? 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-2019-12646 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