CVE-2025-39839: Debian Linux

High severity, CVSS 7.1. EPSS: 0.3% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: batman-adv: fix OOB read/write in network-coding decode batadv_nc_skb_decode_packet() trusts coded_len and checks only against skb->len. XOR starts at sizeof(struct batadv_unicast_packet), reducing payload headroom, and the source skb length is not verified, allowing an out-of-bounds read and a small out-of-bounds write. Validate that coded_len fits within the payload area of both destination and source sk_buffs before XORing.

Affected products

• Debian Debian Linux: version 11.0 only
• Linux Linux Kernel: from 3.10, 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 2025-09-19. Last modified 2026-07-30.