Bug 2516627 (CVE-2026-72235)

Summary: CVE-2026-72235 kernel: batman-adv: retrieve ethhdr after potential skb realloc on RX
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel (batman-adv component). The batadv_interface_rx() function, responsible for handling network packets, can reallocate its internal buffer. However, a pointer to the ethernet header is not correctly updated after this reallocation. This oversight leads to a use-after-free vulnerability, where the system attempts to access memory that has already been released. A remote attacker could potentially exploit this to cause a denial of service (DoS) or disclose sensitive information, impacting network traffic processing and isolation.
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Description OSIDB Bzimport 2026-08-15 06:22:43 UTC 
In the Linux kernel, the following vulnerability has been resolved:

batman-adv: retrieve ethhdr after potential skb realloc on RX

pskb_may_pull() in batadv_interface_rx() 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 VLAN header but missed for the ethernet
header which is later used for the TT and AP isolation handling.
Comment 1 Keith Grant 2026-08-18 16:56:06 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081550-CVE-2026-72235-ab89@gregkh/T