CVE-2026-74436: Linux kernel · rxrpc: serialize kernel accept preallocation with socket teardown
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.8 Critical · fixed in 7.0.0-1013.13~24.04.1 : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 33% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 7.0.0-1013.13~24.04.1, 7.0.0-1017.17~24.04.1, 7.0.0-1016.16~24.04.1 +13
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 15 Aug 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 should be applied to affected Linux Azure kernel versions. The vendor advisory confirms the issue has been resolved by serializing access to the backlog with the socket lock and rejecting kernel preallocation during teardown. Users should update to patched kernel versions to mitigate this vulnerability.
Description
A vulnerability in the Linux kernel's rxrpc subsystem was resolved that involved improper synchronization between kernel accept preallocation and socket teardown. The flaw allowed a kernel preallocation worker to use a freed backlog structure due to a race condition. This could lead to memory corruption and potential system compromise. The issue affects specific Linux Azure kernel versions and has a high CVSS score of 9.8. A patch is available to serialize state checks and backlog lookups with the socket lock, preventing use-after-free conditions.
References
- nvd.nist.gov/vuln/detail/CVE-2026-74436 (opens in a new tab)
- git.kernel.org/stable/c/0337cdba0c477f176c0459bed012109453184573 (opens in a new tab)
- git.kernel.org/stable/c/1741378a7a83dfd8e53a9196730df709b903cd33 (opens in a new tab)
- git.kernel.org/stable/c/35a967ff8b24db09ee429c39c5b5e6571639997d (opens in a new tab)
- git.kernel.org/stable/c/dc175389b18c29a5303ee83169ec653adfae3e17 (opens in a new tab)
- git.kernel.org/stable/c/dfa0b2bbc5e50119f89c6b5407faa5ed86dfa7c5 (opens in a new tab)
- ubuntu.com/security/CVE-2026-74436 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-74436 (opens in a new tab)
- git.kernel.org/linus/dc175389b18c29a5303ee83169ec653adfae3e17 (opens in a new tab)
- ubuntu.com/security/notices/USN-8781-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8816-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8816-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8816-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8816-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8888-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8888-2 (opens in a new tab)