CVE-2026-63823: Linux kernel · keys: Pin request_key_auth payload in instantiate paths
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1117.124~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1122.131~20.04.1 +43
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available and has been released by the Linux kernel maintainers and Ubuntu. Users should update their Linux kernel to the fixed versions as provided in the Ubuntu security notice USN-8726-1. After updating, a system reboot is required to apply the fixes. Due to ABI changes, recompilation and reinstallation of third-party kernel modules may be necessary. No additional mitigation steps are required beyond applying the official patches.
Description
A use-after-free vulnerability in the Linux kernel's key management subsystem (request_key_auth payload handling) has been resolved. The flaw involves improper reference counting of the request_key_auth payload during key instantiation, which could lead to use-after-free conditions. This vulnerability has a high severity rating with a CVSS score of 7.8. The issue affects multiple Linux kernel versions prior to 7.0.0-31.31 and specific older versions. A patch is available and should be applied to mitigate the risk.
References
- nvd.nist.gov/vuln/detail/CVE-2026-63823 (opens in a new tab)
- git.kernel.org/stable/c/35ab4db86774d82389e4b9559e26ab7f68d8e395 (opens in a new tab)
- git.kernel.org/stable/c/4982bfabce6b33b3c9eddb4fb900fe5568b7cf91 (opens in a new tab)
- git.kernel.org/stable/c/708709c65a1832a99b0eef8ae46e343ddaca3d06 (opens in a new tab)
- git.kernel.org/stable/c/7216ce8cb12fee44e309503955bb83806b106129 (opens in a new tab)
- git.kernel.org/stable/c/83c0a1cb296d955d5f4d1f0bd8a769ba8ed8c29f (opens in a new tab)
- git.kernel.org/stable/c/d8274181b0f28d450b42489723a5ba81042158d7 (opens in a new tab)
- git.kernel.org/stable/c/f9b68632ac93cc742f2e411021c4dbfe452ea0c2 (opens in a new tab)
- git.kernel.org/stable/c/fd15b457a86939c38aa12116adabd8ff686c5e51 (opens in a new tab)
- ubuntu.com/security/CVE-2026-63823 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-63823 (opens in a new tab)
- git.kernel.org/linus/fd15b457a86939c38aa12116adabd8ff686c5e51 (opens in a new tab)
- msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-63823.json (opens in a new tab)
- support.microsoft.com/lifecycle (opens in a new tab)
- first.org/cvss (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8727-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8800-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8878-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8879-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8877-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8886-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-2 (opens in a new tab)