CVE-2025-40084
Published Oct 29, 2025
Modified Apr 15, 2026
Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: transport_ipc: validate payload size before reading handle handle_response() dereferences the payload as a 4-byte handle without verifying that the declared payload size is at least 4 bytes. A malformed or truncated message from ksmbd.mountd can lead to a 4-byte read past the declared payload size. Validate the size before dereferencing. This is a minimal fix to guard the initial handle read.
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References
Other References
https://git.kernel.org/stable/c/2dc125f5da134c0915a840b62565c60a595673dd
https://git.kernel.org/stable/c/6f40e50ceb99fc8ef37e5c56e2ec1d162733fef0
https://git.kernel.org/stable/c/867ffd9d67285612da3f0498ca618297f8e41f01
https://git.kernel.org/stable/c/898d527ed94c19980a4d848f10057f1fed578ffb
https://git.kernel.org/stable/c/a02e432d5130da4c723aabe1205bac805889fdb2
Frequently Asked Questions
What is CVE-2025-40084? +
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: transport_ipc: validate payload size before reading handle
handle_response() dereferences the payload as a 4-byte handle without
verifying that the declared payload size is at least 4 bytes. A malformed
or truncated message from ksmbd.mountd can lead to a 4-byte read past the
declared payload size. Validate the size before dereferencing.
This is a minimal fix to guard the initial handle read.
How do I check if I'm vulnerable to CVE-2025-40084? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.