CVE-2025-37879
A bug in the Linux kernel’s 9p network protocol could let a malicious server trick the client into treating a negative read/write count as a large positive number, potentially causing a null pointer dereference. The issue has been fixed in the kernel source.
An official fix is available, so this entry is kept for 30 days and then removed automatically.
Who is affected
Linux kernel users, including Debian 11.0, who run a kernel version before the patch.
Real-world impact
An attacker controlling a 9p server could cause the client to crash or potentially exploit the null pointer dereference to gain code execution on the client machine.
Why this severity
The CVSS score of 9.8 reflects that the vulnerability is exploitable over the network, requires no user interaction, and can lead to complete compromise of confidentiality, integrity, and availability.
What to do about it
- 01Upgrade your Linux kernel to a version that includes the fix.
- 02Reboot the system to load the updated kernel.
NVD description
Timeline
- May 9, 2025 · May 9, 2025PublishedDisclosed and added to the National Vulnerability Database.
- Jul 30, 2026 · 7d agoAdvisory updatedThe NVD record was last revised.
- Jul 30, 2026 · 6d agoOfficial fix availableA vendor patch or mitigation now exists — see the remediation steps above.
How it’s attacked
References & advisories
- git.kernel.org/stable/c/374e4cd75617c8c255…patch
- git.kernel.org/stable/c/468ff4a7c61fb811c5…patch
- git.kernel.org/stable/c/a68768e280b7d0c967…patch
- git.kernel.org/stable/c/c548f95688e2b5ae0e…patch
- git.kernel.org/stable/c/d0259a856afca31d69…patch
- lists.debian.org/debian-lts-announce/2025/05…mailing listthird party advisory