CVE-2026-80876: Linux kernel · ring-buffer: Fix event length with forced 8-byte alignment
Affects Linux kernelSource GCVE Database
Not known to be exploited · fixed in 5.15.0-1117.124~20.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 12:55 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 12% 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 +40
Exploitation evidence
Disclosed: evidence found.
CVE published 4 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
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 that corrects the event length calculation in the ring-buffer subsystem. Users should apply the official Linux kernel updates that include this fix. The vendor advisory confirms that this issue has been resolved in updated kernel versions.
Description
A vulnerability in the Linux kernel's ring-buffer event length calculation was fixed. When the RB_FORCE_8BYTE_ALIGNMENT flag is true, the event length calculation incorrectly adds an extra 4 bytes unconditionally for small events, causing inconsistent data length reporting. This was observed on riscv64 architectures with 64-bit aligned access enabled. The fix adjusts the calculation to correctly subtract the size of the length field when the alignment flag is set, ensuring consistent event length reporting.
References
- nvd.nist.gov/vuln/detail/CVE-2026-80876 (opens in a new tab)
- git.kernel.org/stable/c/14057268e79654c3e8ea2c9b5204cb9644b2964d (opens in a new tab)
- git.kernel.org/stable/c/24c3fa71f9947b0e1f3b954db1b769b44140192e (opens in a new tab)
- git.kernel.org/stable/c/3a63a11897c7ba32d1be7a3fdbc48a8b01cf4992 (opens in a new tab)
- git.kernel.org/stable/c/7c9f0ccf9f04142458d2ac3d39414f4acae242f0 (opens in a new tab)
- git.kernel.org/stable/c/c37e0a4b79a6bbb96ce5ffe279d7c001e20529e0 (opens in a new tab)
- git.kernel.org/stable/c/cfada73fabe2ccc06ec77fe2ceaa088689213326 (opens in a new tab)
- git.kernel.org/stable/c/dbcb8635b1eb7603818591cf745c7b1d714f7ac6 (opens in a new tab)
- git.kernel.org/stable/c/ec5e96aee75d27779b9a860307679f13f33adb0c (opens in a new tab)
- ubuntu.com/security/CVE-2026-80876 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-80876 (opens in a new tab)
- git.kernel.org/linus/c37e0a4b79a6bbb96ce5ffe279d7c001e20529e0 (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-8888-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8889-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8887-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8888-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8887-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8887-3 (opens in a new tab)