CVE-2026-89949: batman-adv: dat: avoid unaligned fault in IP extraction
In the Linux kernel, the following vulnerability has been resolved:
batman-adv: dat: avoid unaligned fault in IP extraction
Independent of the alignment of the ARP packet in the SKB, either the batadvarpipsrc or the batadvarpipdst will have an unaligned access (on HW without native unaligned read support).
Use getunaligned() to handle this properly on all architectures.
Event History
Frequently Asked Questions
Which systems are exposed to this issue?
Systems using the Linux kernel batman-adv module's distributed ARP table (DAT) functionality are relevant. The fault specifically affects hardware architectures without native support for unaligned reads.
What traffic or condition is needed to trigger the fault?
The issue occurs when batman-adv extracts source or destination IP information from an ARP packet whose placement in the socket buffer results in an unaligned access. One of the two IP extraction paths can be unaligned regardless of the ARP packet's alignment in the SKB.
What can be done if an update cannot be applied immediately?
The provided information identifies the affected code path as batman-adv DAT processing of ARP packets, but does not provide a documented temporary mitigation. Prioritize applying a kernel update containing the get_unaligned() fix, particularly on architectures without native unaligned-read support.