CVE-2026-80839
Received Received - Intake

Memory Corruption in Linux Kernel via batman-adv Multicast TVLV

Publication date: 2026-09-04

Last updated on: 2026-09-04

Assigner: kernel.org

Description
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.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-09-04
Last Modified
2026-09-04
Generated
2026-09-04
AI Q&A
2026-09-04
EPSS Evaluated
N/A
NVD
CVE-2026-80839
EUVD
EUVD-2026-71289

Affected Vendors & Products

Currently, no data is known.

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-UNKNOWN

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

This vulnerability in the Linux kernel involves the batman-adv protocol. It occurs when multicast TVLV offsets in network packets exceed the 16-bit limit for transport header fields. The system fails to validate these offsets, leading to incorrect memory access and potential buffer overflows.

Detection Guidance

This vulnerability affects the Linux kernel's batman-adv module. Detection requires checking kernel logs for related errors or examining batman-adv module behavior during multicast TVLV processing. No specific commands are provided in the context.

Impact Analysis

An attacker could exploit this to cause denial-of-service by crashing the system or execute arbitrary code by accessing unauthorized memory. Systems using batman-adv for mesh networking are particularly at risk.

Mitigation Strategies

Update the Linux kernel to a patched version that includes the fix for batman-adv multicast TVLV handling. Monitor kernel security advisories for updates to the batman-adv module.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-80839. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart