CVE-2026-80731: Linux kernel · net: remove CAP_SYS_RAWIO zero-padding in dev_validate_header
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 3% 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 +26
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 3 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 removes the zero-padding branch in dev_validate_header(), eliminating the out-of-bounds write. Users should apply the official Linux kernel updates that address this issue. Since the vulnerability is fixed in updated kernel versions, no additional mitigation steps are required.
Description
A vulnerability in the Linux kernel's network subsystem involving the dev_validate_header() function was resolved. The issue arises when CAP_SYS_RAWIO holders trigger zero-padding of short link layer headers, potentially causing an out-of-bounds write if the device's hard_header_len increases concurrently. This vulnerability affects variable length Layer 2 protocols and could lead to memory corruption. The problematic code path has been removed, eliminating the memory safety risk. The vulnerability has a CVSS score of 7.8 and is considered medium severity. Multiple specific Linux kernel versions are affected. A patch is available to address this issue.
References
- nvd.nist.gov/vuln/detail/CVE-2026-80731 (opens in a new tab)
- git.kernel.org/stable/c/3b9a324e646d3657a8d9806dfbfe4f3e4066e882 (opens in a new tab)
- git.kernel.org/stable/c/53fd7f912c0877647d6a1e1877f5ea8535ee0b4a (opens in a new tab)
- git.kernel.org/stable/c/74e035f07f53feca09e2352e77fccb09cad5e208 (opens in a new tab)
- git.kernel.org/stable/c/8fc9816404166a90ed8d544dc52482fafffb6d9f (opens in a new tab)
- git.kernel.org/stable/c/99df6b7a713f96eda206680d100b76e15f9d9b69 (opens in a new tab)
- git.kernel.org/stable/c/b0f92a5731dc82556a9ae005cc35f71ab136307b (opens in a new tab)
- git.kernel.org/stable/c/dbb30dc943a93e083f1e531bfdc6779e57de40d0 (opens in a new tab)
- git.kernel.org/stable/c/fa6d98dd925e72fc028b26a0cbbff9d2f0601ff6 (opens in a new tab)
- git.kernel.org/stable/c/fc902f52a02298c7432b2334c0c82a2885a1a8b6 (opens in a new tab)
- ubuntu.com/security/CVE-2026-80731 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-80731 (opens in a new tab)
- git.kernel.org/linus/3b9a324e646d3657a8d9806dfbfe4f3e4066e882 (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-8875-2 (opens in a new tab)