CVE-2025-22038: Linux kernel · ksmbd: validate zero num_subauth before sub_auth is accessed
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 8.3 High · fixed in 6.8.0-1041.43~22.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 10:12 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 47% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1041.43~22.04.1, 6.8.0-1041.47~22.04.1, 6.8.0-1042.45~22.04.1 +33
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:HExploitation evidence
Disclosed: evidence found.
CVE published 16 Apr 2025
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 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux@6.8.0-86.87?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws@6.8.0-1041.43?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure@6.8.0-1041.47?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11@6.11.0-1018.18~24.04.1?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-fde-6.17pkg:deb/ubuntu/linux-azure-fde-6.17@6.17.0-1017.17~24.04.1?arch=source&distro=nobleOther 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 applied in updated Linux kernel releases as per the Ubuntu advisory USN-7594-1. Users should update their Linux kernel to the fixed versions provided by their distribution. No additional mitigation is required once the patch is applied.
Description
A vulnerability in the Linux kernel's ksmbd component allowed an out-of-bounds read due to accessing sub_auth without validating that num_subauth was non-zero. This flaw has been fixed by adding a validation step to ensure num_subauth is not zero before access. The issue affects specific Linux kernel versions and has a CVSS score of 8.3, indicating high impact on confidentiality and availability. The vulnerability is patched in updated Linux kernel releases as per the Ubuntu advisory.
References
- ubuntu.com/security/CVE-2025-22038 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-22038 (opens in a new tab)
- git.kernel.org/linus/bf21e29d78cd2c2371023953d9c82dfef82ebb36 (opens in a new tab)
- git.kernel.org/stable/c/0e36a3e080d6d8bd7a34e089345d043da4ac8283 (opens in a new tab)
- git.kernel.org/stable/c/3ac65de111c686c95316ade660f8ba7aea3cd3cc (opens in a new tab)
- git.kernel.org/stable/c/56de7778a48560278c334077ace7b9ac4bfb2fd1 (opens in a new tab)
- git.kernel.org/stable/c/68c6c3142bfcdb049839d40a9a59ebe8ea865002 (opens in a new tab)
- git.kernel.org/stable/c/bf21e29d78cd2c2371023953d9c82dfef82ebb36 (opens in a new tab)
- git.kernel.org/stable/c/c8bfe1954a0b89e7b29b3a3e7f4c5e0ebd295e20 (opens in a new tab)
- ubuntu.com/security/notices/USN-7594-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7594-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7605-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7606-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7605-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7594-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7628-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7835-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7835-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7835-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7835-4 (opens in a new tab)