CVE-2026-22991: Linux kernel · libceph: make free_choose_arg_map() resilient to partial allocation
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.5 High · fixed in 5.15.0-1103.110~20.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 10:12 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 40% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1103.110~20.04.1, 5.15.0-1110.119~20.04.1, 5.15.0-1114.123~20.04.1 +58
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 23 Jan 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 25.10linuxpkg:deb/ubuntu/linux@6.17.0-40.40?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1019.19?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1020.20?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp@6.17.0-1020.22?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1018.18?arch=source&distro=questingOther 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 included in official Linux kernel updates distributed by Ubuntu. Users should update to the fixed kernel versions as listed in the Ubuntu security notices USN-8096-1 and USN-8096-2. After updating, a system reboot is required to apply the changes. Due to an ABI change, recompilation and reinstallation of all third-party kernel modules is necessary. No other mitigations are required as the issue is resolved by the official fix.
Description
A vulnerability in the Linux kernel's libceph component could cause a NULL pointer dereference in the free_choose_arg_map() function when partial memory allocation fails. This issue has been resolved in updated kernel versions. The flaw could lead to a denial of service due to kernel crash. Multiple Linux kernel subsystems were also fixed in related updates. The vulnerability is rated medium severity with a CVSS score of 7.5. Patches are available and included in Ubuntu security updates requiring system reboot and recompilation of third-party kernel modules.
References
- ubuntu.com/security/CVE-2026-22991 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-22991 (opens in a new tab)
- git.kernel.org/linus/e3fe30e57649c551757a02e1cad073c47e1e075e (opens in a new tab)
- git.kernel.org/stable/c/8081faaf089db5280c3be820948469f7c58ef8dd (opens in a new tab)
- git.kernel.org/stable/c/851241d3f78a5505224dc21c03d8692f530256b4 (opens in a new tab)
- git.kernel.org/stable/c/9b3730dabcf3764bfe3ff07caf55e641a0b45234 (opens in a new tab)
- git.kernel.org/stable/c/c4c2152a858c0ce4d2bff6ca8c1d5b0ef9f2cbdf (opens in a new tab)
- git.kernel.org/stable/c/e3fe30e57649c551757a02e1cad073c47e1e075e (opens in a new tab)
- git.kernel.org/stable/c/ec1850f663da64842614c86b20fe734be070c2ba (opens in a new tab)
- git.kernel.org/stable/c/f21c3fdb96833aac2f533506899fe38c19cf49d5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8096-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8096-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8096-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8096-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8116-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8096-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8141-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8163-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8163-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8243-1 (opens in a new tab)