CVE-2025-39839 batman-adv: fix OOB read/write in network-coding decode
An out-of-bounds read and write in the batman-adv network-coding decode function allows attackers to potentially execute code or cause a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-39839?
CVE-2025-39839 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 19 Sep 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Weakness: CWE-125
Which versions are affected by CVE-2025-39839?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-39839?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2025-39839 being exploited?
There is no known exploitation of CVE-2025-39839 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as AZL-67514, AZL-74826, BELL-CVE-2025-39839, DEBIAN-CVE-2025-39839, GHSA-2j47-jhvw-fgmm, ROOT-OS-DEBIAN-11-CVE-2025-39839 and 5 more.