CVE-2025-38051: Linux kernel · smb: client: Fix use-after-free in cifs_fill_dirent
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1090.97~20.04.1 : patch Linux kernel soon.
Data as of 28 Oct 2026, 11:30 UTC
- Patch
- Available – fixed in 5.15.0-1090.97~20.04.1, 5.15.0-1094.103~20.04.1, 5.15.0-1090.99~20.04.1 +63
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 18 Jun 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.
Patches and advisories
- ubuntu.com/security/notices/USN-7704-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7704-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7704-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7704-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7711-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7712-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7704-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-7712-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7769-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7770-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7771-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7769-2 (opens in a new tab)
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 addressing this vulnerability is available and included in multiple updated Linux kernel versions as detailed in the Ubuntu advisory USN-7704-1. Users should update their Linux kernel packages to the fixed versions and reboot their systems to apply the changes. Due to an ABI change, recompilation and reinstallation of third-party kernel modules may be necessary. No additional mitigation steps are required beyond applying the official updates.
Description
A use-after-free vulnerability was identified and fixed in the Linux kernel's SMB client code, specifically in the cifs_fill_dirent function. This flaw arises from a race condition during directory read concurrency, which can lead to accessing freed memory, causing a kernel memory safety violation detected by KASAN. The issue affects multiple Linux kernel versions and has been addressed in several patched releases. The vulnerability has a high severity score and could allow an attacker with local privileges to compromise system integrity. A fix is available and included in updated Linux kernel packages. Users should apply the updates and reboot to mitigate the risk.
References
- ubuntu.com/security/CVE-2025-38051 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-38051 (opens in a new tab)
- git.kernel.org/linus/a7a8fe56e932a36f43e031b398aef92341bf5ea0 (opens in a new tab)
- git.kernel.org/stable/c/1b197931fbc821bc7e9e91bf619400db563e3338 (opens in a new tab)
- git.kernel.org/stable/c/73cadde98f67f76c5eba00ac0b72c453383cec8b (opens in a new tab)
- git.kernel.org/stable/c/9bea368648ac46f8593a780760362e40291d22a9 (opens in a new tab)
- git.kernel.org/stable/c/9c9aafbacc183598f064902365e107b5e856531f (opens in a new tab)
- git.kernel.org/stable/c/a24c2f05ac3c5b0aaa539d9d913826d2643dfd0e (opens in a new tab)
- git.kernel.org/stable/c/a7a8fe56e932a36f43e031b398aef92341bf5ea0 (opens in a new tab)
- git.kernel.org/stable/c/aee067e88d61eb72e966f094e4749c6b14e7008f (opens in a new tab)
- git.kernel.org/stable/c/c8623231e0edfcccb7cc6add0288fa0f0594282f (opens in a new tab)
- ubuntu.com/security/notices/USN-7704-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7704-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7704-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7704-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7711-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7712-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7704-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-7712-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7769-1 (opens in a new tab)