Out-of-Bounds Read/Write Vulnerability in Linux Kernel Affecting batman-adv

CVE-2025-39839

What is CVE-2025-39839?

A vulnerability has been identified in the Linux kernel's batman-adv component, specifically within the network coding decode process. The function batadv_nc_skb_decode_packet() is susceptible to an out-of-bounds read and a small out-of-bounds write due to improper validation of the 'coded_len' parameter. This vulnerability occurs as the function only checks 'coded_len' against 'skb->len', ignoring essential checks on the source skb length. As a result, if 'coded_len' exceeds the appropriate boundaries, it may lead to potential memory corruption. The issue has been addressed by implementing tighter validation to ensure that 'coded_len' is within the acceptable range of both destination and source sk_buffs.

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