Executive brief
The batman-adv mesh networking module in the Linux kernel improperly handled memory access when parsing ARP packets, potentially causing hardware exceptions on systems that don't support unaligned memory reads. This could trigger kernel panics or system instability when the module processes network traffic. The fix uses safe memory access primitives to ensure compatibility across all CPU architectures.
Technical details
This vulnerability is an unaligned memory access bug in the batman-adv Distributed ARP Table (DAT) implementation. The functions batadv_arp_ip_src() and batadv_arp_ip_dst() directly dereference pointers that may not be naturally aligned, causing CPU faults on architectures without hardware support for unaligned reads (such as ARM and older PowerPC systems). The fix wraps these memory reads with get_unaligned() macros, which safely handle misaligned access across all platforms. No authentication or special network conditions are required—the vulnerability triggers automatically when the kernel processes certain ARP packet structures. Patches are available in the Linux kernel stable branches.
Affected products
- Linux Linux kernel Multiple versions (batman-adv module; fix applied to 2.6.x through 7.x branches
Timeline
- 2026-09-16: disclosed: Advisory published
- 2026-07-06: patched: Fix committed upstream by Sven Eckelmann