CVE-2026-72234 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
batman-adv: access unicast_ttvn skb->data only after skb realloc
The pskb_may_pull() called by batadv_get_vid() could reallocate the buffer behind the skb. Variables which were pointing to the old buffer need to be reassigned to avoid an use-after-free.
This was done correctly for the ethernet header but missed for the unicast_packet pointer.
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Analysis
by VulDB Data Team • 08/15/2026
The vulnerability in question affects the batman-adv kernel module, which implements the Better Approach to Mobile Ad-hoc Networking routing protocol. This protocol is designed to provide efficient routing capabilities for wireless mesh networks and operates at the network layer of the Linux kernel. The specific flaw exists within the batadv_get_vid() function where improper handling of socket buffer (skb) memory management creates a potential use-after-free condition that could be exploited by malicious actors.
The technical implementation of this vulnerability stems from a failure to properly account for buffer reallocation during packet processing. When batadv_get_vid() invokes pskb_may_pull(), this function may trigger a reallocation of the underlying socket buffer data structure. The code correctly handles the ethernet header pointer reassignment following this potential reallocation, but fails to update the unicast_packet pointer that references the old buffer location. This oversight creates a scenario where subsequent operations on the unicast_packet pointer access memory that has already been freed or repurposed, leading to undefined behavior and potential security implications.
The operational impact of this vulnerability extends beyond simple kernel crashes, potentially allowing attackers to execute arbitrary code with kernel privileges or cause denial of service conditions within mesh network environments. The use-after-free condition could be leveraged through crafted network packets that trigger the vulnerable code path during packet processing in wireless mesh networks. This presents particular risk in environments where batman-adv is deployed for critical infrastructure communications, as it could compromise network availability and data integrity.
The vulnerability aligns with CWE-416, which describes use-after-free conditions in software implementations, and maps to attack techniques within the ATT&CK framework under T1059 for command and control through kernel-level exploits. Mitigation strategies should include applying the official kernel patch that ensures proper reassignment of all pointers following buffer reallocation, implementing kernel memory protection mechanisms such as kASLR and SMEP/SMAP, and conducting thorough network monitoring to detect anomalous packet processing behavior. Additionally, system administrators should consider limiting mesh network exposure through proper firewall configurations and maintaining up-to-date kernel versions to prevent exploitation of this class of vulnerabilities that could lead to complete system compromise in wireless mesh network deployments.
This vulnerability represents a critical memory safety issue that demonstrates the importance of careful buffer management in kernel-space code, particularly when dealing with packet processing functions that may trigger memory reallocation operations. The fix requires comprehensive pointer validation and reassignment throughout the affected code path to ensure all references remain valid after potential buffer modifications, emphasizing the need for rigorous testing of memory management operations in kernel modules handling network traffic.