CVE-2026-31614: Linux kernel · smb: client: fix off-by-8 bounds check in check_wsl_eas()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.1 High · fixed in 7.0.0-28.28~24.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 7.0.0-28.28~24.04.1, 7.0.0-27.27, 7.0.0-1008.8 +6
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 24 Apr 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-ibmpkg:deb/ubuntu/linux-ibm?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 has been released by Ubuntu and other Linux distributions. Users should update their Linux kernel to the fixed versions listed in the vendor advisory and reboot their systems to apply the changes. Due to an ABI change in the kernel update, recompilation and reinstallation of third-party kernel modules may be required. Follow the vendor's update instructions carefully to ensure full remediation.
Description
A high-severity vulnerability in the Linux kernel SMB client was fixed involving an off-by-8 bounds check error in the check_wsl_eas() function. The flaw allowed an untrusted SMB server to leak up to 8 bytes of kernel heap memory during extended attribute (EA) name comparison, potentially influencing Windows Subsystem for Linux (WSL) extended attribute interpretation. The issue was due to incorrect pointer arithmetic in bounds checking, leading to out-of-bounds reads. This vulnerability affects multiple Linux kernel versions prior to specific patched releases. A patch is available and included in recent Linux kernel updates distributed by Ubuntu.
References
- ubuntu.com/security/CVE-2026-31614 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-31614 (opens in a new tab)
- git.kernel.org/linus/3d8b9d06bd3ac4c6846f5498800b0f5f8062e53b (opens in a new tab)
- ubuntu.com/security/notices/USN-8488-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8488-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8507-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8569-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8603-1 (opens in a new tab)