CVE-2025-40103
In the Linux kernel, the following vulnerability has been resolved: smb: client: Fix refcount leak for cifs_sb_tlink Fix three refcount inconsistency issues related to `cifs_sb_tlink`. Comments for `cifs_sb_tlink` state that `cifs_put_tlink()` needs to be called after successful calls to `cifs_sb_tlink()`. Three calls fail to update refcount accordingly, leading to possible resource leaks.
Affected versions
Linux kernel versions
3.7
and later are affected. Fixed in
5.15.203,
6.1.158,
6.6.114,
6.12.55,
6.17.5,
6.18
and their respective stable series.
References
The following references provide additional information about CVE-2025-40103 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.
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PatchKernel patch commithttps://git.kernel.org/stable/c/790282abe9d805f08618c1c24ea2529e7259b692
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PatchKernel patch commithttps://git.kernel.org/stable/c/896bb31e1416f582503db1350cf1bd10dc64e5a6
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PatchKernel patch commithttps://git.kernel.org/stable/c/c2b77f42205ef485a647f62082c442c1cd69d3fc
Frequently asked questions
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What is CVE-2025-40103?
CVE-2025-40103 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 3.7 onward and has been patched in 5.15.203, 6.1.158, 6.6.114 and others. CVE-2025-40103 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2025-40103?
Yes — CVE-2025-40103 has been patched. Fixed versions include 5.15.203, 6.1.158, 6.6.114 and others. If you are running Linux kernel 3.7 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2025-40103 actively exploited?
No — CVE-2025-40103 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.