CVE-2026-63831: Linux kernel · mac802154: llsec: add skb_cow_data() before in-place crypto
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 8.8 High · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 23% 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 +43
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Jul 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 to affected Linux kernel versions. The fix involves updating the kernel to versions that include the skb_cow_data() call before in-place crypto operations in the mac802154 llsec subsystem. After applying the update, a system reboot is required. No additional mitigation steps are necessary as the issue is resolved by the official kernel update.
Description
A vulnerability in the Linux kernel's mac802154 llsec subsystem allowed in-place cryptographic operations on shared socket buffer (skb) data without ensuring data uniqueness. This could cause silent data corruption, use-after-free errors, and kernel crashes under concurrent 802.15.4 traffic with security enabled. The issue was fixed by adding a call to skb_cow_data() before in-place crypto operations to ensure the skb data is not shared and safe to modify.
References
- nvd.nist.gov/vuln/detail/CVE-2026-63831 (opens in a new tab)
- git.kernel.org/stable/c/3a2b378b3a9ca75d3518d879148d2ad25b5714a9 (opens in a new tab)
- git.kernel.org/stable/c/7a831bcd0486788283ef35e396d4282ee01bb0d5 (opens in a new tab)
- git.kernel.org/stable/c/84a04eb5b210643bd67aab81ff805d32f62aa865 (opens in a new tab)
- git.kernel.org/stable/c/86d531337ea1ba02d9f2bc830d07c683d9bfaade (opens in a new tab)
- git.kernel.org/stable/c/993fd674fe85d114e6a8d3963033d4fbbc2170a8 (opens in a new tab)
- git.kernel.org/stable/c/bd968bdd568beacfdf98ec537a87527e85f1d0cf (opens in a new tab)
- git.kernel.org/stable/c/e28e7fd34c449028325322a3f5127b92594b7396 (opens in a new tab)
- git.kernel.org/stable/c/ff976ef7c39199ebff33c18034636595016db9f0 (opens in a new tab)
- ubuntu.com/security/CVE-2026-63831 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-63831 (opens in a new tab)
- git.kernel.org/linus/84a04eb5b210643bd67aab81ff805d32f62aa865 (opens in a new tab)
- msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-63831.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-8726-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8727-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8781-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8800-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8760-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8726-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8728-3 (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)