CVE-2026-72232 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
batman-adv: ensure minimal ethernet header on TX
As documented in commit 8bd67ebb50c0 ("net: bridge: xmit: make sure we have at least eth header len bytes"), it is possible by for a local user with eBPF TC hook access to attach a tc filter which truncates the packet and redirects to an batadv interface. But the code assumes that at least ETH_HLEN bytes are available and thus might read outside of the available buffer.
The batadv_interface_tx() must therefore always check itself if enough data is available for the ethernet header and don't rely on min_header_len.
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Analysis
by VulDB Data Team • 08/15/2026
The vulnerability in question affects the batman-adv Linux kernel module, which implements the Better Approach to Mobile Ad-hoc Networking protocol for wireless mesh networks. This particular flaw stems from insufficient validation of packet buffer boundaries during transmission operations, creating a potential memory access violation that could be exploited by local attackers with specific privileges.
The technical root cause involves the batadv_interface_tx() function's reliance on incorrect assumptions about packet header availability within network buffers. While other kernel components like net bridge implementations have addressed similar issues through proper buffer length validation as documented in commit 8bd67ebb50c0, the batman-adv module fails to perform adequate checks before accessing ethernet header data. This discrepancy creates a scenario where malicious code can manipulate packet structures through eBPF TC hooks to truncate packets and redirect them to batadv interfaces, ultimately causing the kernel to read beyond allocated buffer boundaries.
The operational impact of this vulnerability manifests when a local user with eBPF traffic control hook access deliberately constructs packet filters that truncate network frames. When these truncated packets reach the batadv interface transmission handler, the code assumes at minimum ETH_HLEN (typically 14 bytes) of ethernet header data is available for processing. However, the truncation may result in insufficient buffer space, leading to kernel memory corruption or potential privilege escalation scenarios. This vulnerability directly aligns with CWE-129 Input Validation and Output Encoding, specifically addressing improper bounds checking in kernel memory management.
Attackers exploiting this weakness could potentially leverage the eBPF TC hook access to create malicious packet redirection chains that consistently trigger the buffer overflow condition. The attack vector requires local system access and specific eBPF capabilities, but once achieved, could result in arbitrary code execution within kernel space or denial of service conditions that compromise network mesh functionality. Mitigation strategies must focus on implementing proper buffer length validation within batadv_interface_tx() before any ethernet header processing occurs, ensuring the minimum required header size is maintained regardless of external packet modifications.
The fix involves modifying the transmission logic to independently verify sufficient buffer space for ethernet headers rather than relying on upstream assumptions about min_header_len values. This approach aligns with defensive programming principles and follows established kernel security practices documented in various ATT&CK framework techniques related to privilege escalation and kernel memory corruption. The resolution ensures that packet processing remains robust even when subjected to malicious manipulation through traffic control mechanisms, thereby maintaining the integrity of mesh network communications and preventing potential exploitation scenarios that could affect wireless network infrastructure.