CVE-2026-97523: Linux kernel · mptcp: close race between scheduler and state change
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.5 High.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 53% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
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 25 Sep 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
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 fix has been implemented to explicitly check and handle the race condition scenario. Users should apply the official patches or updates provided for the affected linux-hwe-edge kernel versions to remediate this issue. Since this is not a cloud service, remediation depends on applying vendor-supplied kernel updates.
Description
A race condition vulnerability in the Linux kernel's Multipath TCP (mptcp) scheduler was resolved. The issue involves a race between the scheduler and subflow socket state changes, which can cause data transmission failures and potentially lead to a divide-by-zero operation during socket release. This vulnerability affects specific versions of the linux-hwe-edge kernel and has a medium severity rating with a CVSS score of 7.5.
References
- ubuntu.com/security/CVE-2026-97523 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-97523 (opens in a new tab)
- git.kernel.org/stable/c/4c856f3c151a2f3fa237caa651c44015916ca584 (opens in a new tab)
- git.kernel.org/stable/c/8f11430d51ff8365bc51b670bc3002b65ae4c6b7 (opens in a new tab)
- git.kernel.org/stable/c/a09c87abf10a0a7e203137c75b5381aa63d9b31d (opens in a new tab)
- git.kernel.org/stable/c/42064de57fb83231fcc89663a94885f228a1ee53 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-97523 (opens in a new tab)
- git.kernel.org/stable/c/0a926b5df8efdfbac07e2fb7fafb21849a2ad9c0 (opens in a new tab)
- git.kernel.org/stable/c/5883ae880f51edc4b1484e787473b865b6159ead (opens in a new tab)
- git.kernel.org/stable/c/d74b2e26b54a7dae1d87c1f19ae0d6db500e5e03 (opens in a new tab)