CVE-2025-39902: Debian Linux

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: mm/slub: avoid accessing metadata when pointer is invalid in object_err() object_err() reports details of an object for further debugging, such as the freelist pointer, redzone, etc. However, if the pointer is invalid, attempting to access object metadata can lead to a crash since it does not point to a valid object. One known path to the crash is when alloc_consistency_checks() determines the pointer to the allocated object is invalid because of a freelist corruption, and calls object_err() to report it. The debug code should report and handle the corruption gracefully and not crash in the process. In case the pointer is NULL or check_valid_pointer() returns false for the pointer, only print the pointer value and skip accessing metadata.

Affected products

• Debian Debian Linux: version 11.0 only
• Linux Linux Kernel: from 2.6.22, before 5.4.299 (fixed in 5.4.299); from 5.5, before 5.10.243 (fixed in 5.10.243); from 5.11, before 5.15.192 (fixed in 5.15.192); from 5.16, before 6.1.151 (fixed in 6.1.151); from 6.2, before 6.6.105 (fixed in 6.6.105); from 6.7, before 6.12.46 (fixed in 6.12.46); …

Published 2025-10-01. Last modified 2026-07-30.