CVE-2025-39942: Linux kernel · ksmbd: smbdirect: verify remaining_data_length respects
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.5 High · fixed in 6.8.0-1050.53~22.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 21% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1050.53~22.04.1, 6.8.0-1051.57~22.04.1, 6.8.0-1058.65~22.04.1 +29
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 4 Oct 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?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-aws-6.14pkg:deb/ubuntu/linux-aws-6.14?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?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 should be applied to affected Linux kernel versions. The vendor advisory from Ubuntu confirms that this and other kernel vulnerabilities have been fixed in updated kernel packages. Users should update to the fixed kernel versions as provided by their Linux distribution's security updates. No additional mitigation steps are indicated by the vendor advisory.
Description
A vulnerability in the Linux kernel's ksmbd smbdirect component was resolved, ensuring that remaining_data_length respects max_fragmented_recv_size. This fix addresses a potential issue related to data length verification inspired by existing checks on data_offset and data_length. The vulnerability affects multiple specific Linux kernel versions and has a CVSS score of 7.5 with a medium severity rating. The vulnerability could lead to denial of service due to an impact on availability. A patch is available as part of security updates.
References
- ubuntu.com/security/CVE-2025-39942 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-39942 (opens in a new tab)
- git.kernel.org/linus/e1868ba37fd27c6a68e31565402b154beaa65df0 (opens in a new tab)
- git.kernel.org/stable/c/196a3a7676d726ee67621ea2bf3b7815ac2685b4 (opens in a new tab)
- git.kernel.org/stable/c/9644798294c7287e65a7b26e35aa6d2ce3345bcc (opens in a new tab)
- git.kernel.org/stable/c/c64b915bb3d9339adcae5db4be2c35ffbef5e615 (opens in a new tab)
- git.kernel.org/stable/c/d3cb3f209d35c44b7ee74f77ed27ebb28995b9ce (opens in a new tab)
- git.kernel.org/stable/c/e1868ba37fd27c6a68e31565402b154beaa65df0 (opens in a new tab)
- ubuntu.com/security/notices/USN-8095-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8100-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8095-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8095-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8095-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8125-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8126-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8095-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8165-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8261-1 (opens in a new tab)