CVE-2026-89771: Linux kernel · ring-buffer: Fix subbuf resize race with ring buffer readers trace_buffer
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 28 Oct 2026, 01:03 UTC
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 11 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 is available and should be applied by updating to patched kernel versions. The affected versions include specific Linux kernel builds such as 4.15.0-1002.2 through 4.15.0-1028.29, 5.0.0-1025.28 through 5.0.0-1027.30, and 5.3.0-1033.35 through 5.3.0-1035.37. Users should upgrade to these fixed versions to mitigate the vulnerability.
Description
A race condition vulnerability in the Linux kernel's ring buffer implementation (trace_buffer) has been fixed. The issue involved unsafe lockless reads of the sub-buffer size during concurrent resizing, which could lead to inconsistent or corrupted data handling. The fix involves using safer accessors and synchronizing buffer modifications with a mutex to prevent race conditions.
References
- ubuntu.com/security/CVE-2026-89771 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89771 (opens in a new tab)
- git.kernel.org/linus/8a5f63637890f03177146efddaba5ec7a1b4d61f (opens in a new tab)
- git.kernel.org/stable/c/0c7c517827a453128a8f58bfd849546a29813b27 (opens in a new tab)
- git.kernel.org/stable/c/50f4a793c4ff24826efb0ac700989a5063cc53df (opens in a new tab)
- git.kernel.org/stable/c/6d666f0b8b36c0765cf19fbe6de5a7ba5a73aad9 (opens in a new tab)
- git.kernel.org/stable/c/8a5f63637890f03177146efddaba5ec7a1b4d61f (opens in a new tab)