CVE-2025-37879: debian linux Out-of-bounds Read — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: 9p/net: fix improper handling of bogus negative read/write replies In p9_client_write() and p9_client_read_once(), if the server incorrectly replies with success but a negative write/read count then we would consider written (negative) <= rsize (positive) because both variables were signed. Make variables unsigned to avoid this problem. The reproducer linked below now fails with the following error instead of a null pointer deref: 9pnet: bogus RWRITE count (4294967295 > 3)

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CVSS v3.1 Score

7.1

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Weakness Type (CWE)

CWE-125 Out-of-bounds Read

Affected Products

Vendor	Product	Versions
linux	linux_kernel	< 6.1.136
linux	linux_kernel	6.2 — 6.6.89
linux	linux_kernel	6.7 — 6.12.26
linux	linux_kernel	6.13 — 6.14.5
debian	debian_linux	All

References

Advisories & Patches

https://git.kernel.org/stable/c/374e4cd75617c8c2552f562f39dd989583f5c330 https://git.kernel.org/stable/c/468ff4a7c61fb811c596a7c44b6a5455e40fd12b https://git.kernel.org/stable/c/a68768e280b7d0c967ea509e791bb9b90adc94a5 https://git.kernel.org/stable/c/c548f95688e2b5ae0e2ae43d53cf717156c7d034 https://git.kernel.org/stable/c/d0259a856afca31d699b706ed5e2adf11086c73b

Other References

https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html

Frequently Asked Questions

What is CVE-2025-37879? +

In the Linux kernel, the following vulnerability has been resolved: 9p/net: fix improper handling of bogus negative read/write replies In p9_client_write() and p9_client_read_once(), if the server incorrectly replies with success but a negative write/read count then we would consider written (negative) <= rsize (positive) because both variables were signed. Make variables unsigned to avoid this problem. The reproducer linked below now fails with the following error instead of a null pointer deref: 9pnet: bogus RWRITE count (4294967295 > 3) It has a CVSS v3.1 base score of 7.1 (HIGH).

How severe is CVE-2025-37879? +

CVE-2025-37879 has a CVSS v3.1 score of 7.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-37879? +

CVE-2025-37879 affects products from debian, linux, specifically: debian_linux, linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-37879? +

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.

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CVE-2025-37879