CVE-2025-37899: Linux kernel · ksmbd: fix use-after-free in session logoff
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 8.8 High · fixed in 6.8.0-1047.50~22.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.8% chance of exploitation in 30 days – higher than 58% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 6.8.0-1047.50~22.04.1, 6.8.0-1051.57~22.04.1, 6.8.0-1048.51~22.04.1 +29
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 20 May 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@6.8.0-101.101?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws@6.8.0-1047.50?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-aws-6.14pkg:deb/ubuntu/linux-aws-6.14@6.14.0-1009.9~24.04.1?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure@6.8.0-1051.57?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– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in session logoff The sess->user object can currently be in use by another thread, for example if another connection has sent a session setup request to bind to the session being free'd. The handler for that connection could be in the smb2_sess_setup function which makes use of sess->user.
References
- ubuntu.com/security/CVE-2025-37899 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-37899 (opens in a new tab)
- git.kernel.org/linus/2fc9feff45d92a92cd5f96487655d5be23fb7e2b (opens in a new tab)
- git.kernel.org/stable/c/02d16046cd11a5c037b28c12ffb818c56dd3ef43 (opens in a new tab)
- git.kernel.org/stable/c/2fc9feff45d92a92cd5f96487655d5be23fb7e2b (opens in a new tab)
- git.kernel.org/stable/c/d5ec1d79509b3ee01de02c236f096bc050221b7f (opens in a new tab)
- ubuntu.com/security/notices/USN-7649-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7650-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7649-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7665-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7665-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7721-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8059-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8059-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8059-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8059-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8059-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8059-6 (opens in a new tab)
- ubuntu.com/security/notices/USN-8059-7 (opens in a new tab)
- ubuntu.com/security/notices/USN-8059-8 (opens in a new tab)