CVE-2026-80839
What it is
In the Linux kernel, the following vulnerability has been resolved: batman-adv: reject unrepresentable multicast TVLV offsets The network and transport header fields in struct sk_buff are 16-bit offsets from skb->head, and U16_MAX is reserved as the unset transport header value. batadv_tvlv_call_handler() sets both fields from a received multicast TVLV without checking whether the TVLV end is representable. If the end offset exceeds the field's range, skb_set_transport_header() truncates it so that the transport header precedes the network header. The negative difference is then returned by skb_network_header_len() as a large u32. batadv_mcast_forw_packet() consequently accepts an oversized multicast tracker and accesses memory beyond the skb data. Add skb_set_transport_header_careful(), an offset-aware counterpart to skb_reset_transport_header_careful(), which validates the final head-relative offset before assigning it. Use the new helper in batadv_tvlv_call_handler() and reject unrepresentable TVLVs before setting the network header.
At a glance
- Exploit odds
- 0.2% chance of exploitation in the next 30 days (EPSS).
- Fix
- No patch or advisory is linked yet. Look at mitigations or restrict exposure.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.2% in the next 30 days (EPSS).
- Severity: not scored yet.
- Fix: none linked yet, which raises it.
Details
- Published
- Last modified
- Exploit probability
- 0.2% · EPSS, next 30 days
- Record status
- Received
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-80839.md and follow it. Check whether this project is affected by CVE-2026-80839. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
References
- https://git.kernel.org/stable/c/1b466746fe109127fd983100a228cdd1f1f6ece2
- https://git.kernel.org/stable/c/2b46baa591d0a7c16b62f150917187e70d053be6
- https://git.kernel.org/stable/c/916ec741e65af072b98e475feaad98c063da1b7c
- https://git.kernel.org/stable/c/da1f5aa7ec93f2cc17f5cd30efc54f62af433cf2
- https://git.kernel.org/stable/c/f12c2de4f542e3220e17e0606f492110064f04cb