CVE-2025-39838: 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: cifs: prevent NULL pointer dereference in UTF16 conversion There can be a NULL pointer dereference bug here. NULL is passed to __cifs_sfu_make_node without checks, which passes it unchecked to cifs_strndup_to_utf16, which in turn passes it to cifs_local_to_utf16_bytes where '*from' is dereferenced, causing a crash. This patch adds a check for NULL 'src' in cifs_strndup_to_utf16 and returns NULL early to prevent dereferencing NULL pointer. Found by Linux Verification Center (linuxtesting.org) with SVACE

Affected products

• Debian Debian Linux: version 11.0 only
• Linux Linux Kernel: from 6.12, before 6.12.46 (fixed in 6.12.46); from 6.13, before 6.16.6 (fixed in 6.16.6); version 6.17 only

Published 2025-09-19. Last modified 2026-06-17.