CVE-2025-37879: Debian Linux

High severity, CVSS 7.1. EPSS: 0.7% chance of exploitation in the next 30 days.

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)

Affected products

• Debian Debian Linux: version 11.0 only
• Linux Linux Kernel: before 6.1.136 (fixed in 6.1.136); from 6.2, before 6.6.89 (fixed in 6.6.89); from 6.7, before 6.12.26 (fixed in 6.12.26); from 6.13, before 6.14.5 (fixed in 6.14.5)

Published 2025-05-09. Last modified 2026-07-30.