CVE-2025-39839

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.

Red Hat Enterprise Linux is not affected by this flaw because the B.A.T.M.A.N. advanced mesh networking subsystem is not compiled into Red Hat kernel packages. On systems running upstream kernels with network-coding support enabled, an attacker with network adjacency could send crafted packets to induce out-of-bounds memory access during decoding operations, potentially leading to a system crash or memory leakage. Because the relevant driver code is not present in supported Red Hat products, default installations are not vulnerable.