CVE-2026-74688: Linux kernel · sctp: clear control chunk transport if it is being removed
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.8 Critical · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 42% 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 +27
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 22 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 promptly. The vendor advisory from Ubuntu confirms that this issue has been fixed in updated Linux kernel packages. Users should update their Linux kernel to the fixed versions and reboot to apply the changes.
Description
A use-after-free vulnerability in the Linux kernel SCTP implementation was resolved. The issue occurs because the SCTP heartbeat acknowledgment chunk caches a transport pointer without proper reference counting. If the peer transport is removed while the chunk is queued, the chunk retains a dangling pointer, leading to a use-after-free when transmitted. This flaw can cause system compromise. A patch is available to clear the cached transport pointer when removing the transport.
References
- nvd.nist.gov/vuln/detail/CVE-2026-74688 (opens in a new tab)
- git.kernel.org/stable/c/18d704bdd809377dfd81a3c2f42426763b5da227 (opens in a new tab)
- git.kernel.org/stable/c/4d6b9cac6df5e0cfef1a66b3edd7aebdb9e4b7e7 (opens in a new tab)
- git.kernel.org/stable/c/6160e756db81d6cb63e3e2952efcf6c5134be385 (opens in a new tab)
- git.kernel.org/stable/c/8de65194a04d2552cd39b6c67d942d490f22d174 (opens in a new tab)
- git.kernel.org/stable/c/936658ec41c28c397ef390140e02d4c91ade92f0 (opens in a new tab)
- git.kernel.org/stable/c/c9158ceaf27780ef64534ad72f44ffde3f8ccc49 (opens in a new tab)
- git.kernel.org/stable/c/dbb3f418a8665ffb0514e1a9520ab6a1c5d4d886 (opens in a new tab)
- git.kernel.org/stable/c/fad4766a74220fe579c6fcaa10ba01c23529814f (opens in a new tab)
- ubuntu.com/security/CVE-2026-74688 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-74688 (opens in a new tab)
- msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74688.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-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)