CVE-2026-64515 in Linux
Summary
by MITRE • 07/25/2026
In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: fix MLE defragmentation
If either reconf or EPCS multi-link element (MLE) is contained in a non-transmitted profile, the defragmentation routine is called with a pointer to the defragmented copy, but the original elements.
This is incorrect for two reasons: - if the original defragmentation was needed, it will not find the correct data - if the original frame is at a higher address, the parsing will potentially overrun the heap data (though given the layout of the buffers, only into the new defragmentation buffer, and then it has to stop and fail once that's filled with copied data.
Fix it by tracking the container along with the pointer and in doing so also unify the two almost identical defragmentation routines.
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Analysis
by VulDB Data Team • 07/26/2026
This vulnerability exists within the linux kernel's mac80211 subsystem which handles wireless networking operations particularly in ieee 80211 environments. The issue manifests in the multi-link element (mle) defragmentation process where improper handling of memory pointers leads to potential security risks. The vulnerability specifically affects wireless devices that utilize multi-link elements in their communication protocols, creating a scenario where memory corruption can occur during frame reassembly operations.
The technical flaw stems from incorrect pointer management during the defragmentation routine execution. When either reconfiguration or extended power save control (epcs) multi-link elements are present in non-transmitted profiles, the system calls the defragmentation routine with a pointer to the defragmented copy while maintaining references to the original elements. This creates a fundamental mismatch where the memory addresses used for processing do not correspond to the actual data location. The flaw operates at the intersection of memory management and wireless protocol parsing, creating opportunities for heap-based memory corruption.
The operational impact of this vulnerability is significant for wireless network security and system stability. An attacker could potentially exploit this issue to cause memory corruption that might lead to system crashes or more severe outcomes including privilege escalation. The potential for heap overruns exists when the original frame data resides at higher memory addresses than expected, allowing parsing operations to access memory regions beyond their intended boundaries. While the attack surface is limited to specific wireless scenarios involving multi-link elements, the vulnerability affects any system running affected kernel versions with wireless capabilities.
The fix implemented resolves this issue by tracking both the container and pointer information during defragmentation operations. This approach unifies two nearly identical defragmentation routines that previously handled different element types separately, thereby reducing code complexity and potential for similar issues. The solution follows established security practices for memory management in kernel space operations, aligning with common vulnerability mitigation strategies. This change ensures proper pointer tracking throughout the defragmentation process and eliminates the mismatch between original and defragmented data references.
This vulnerability relates to several cybersecurity standards and frameworks including cwe-121 which covers buffer overflow conditions, and cwe-787 which addresses out-of-bounds write operations. The flaw also maps to attack techniques described in the mitre att&ck framework under privilege escalation and memory corruption categories. The fix demonstrates proper defensive programming practices for kernel-level memory management and wireless protocol handling, emphasizing the importance of maintaining consistency between data references and actual memory locations during complex parsing operations.
The resolution addresses fundamental issues in how wireless frame reassembly operates within linux kernel wireless subsystems. By unifying the defragmentation routines and properly tracking element containers, the fix eliminates potential memory access violations that could be exploited by malicious actors. This change improves overall system stability for wireless devices while reducing the attack surface for memory corruption exploits. The solution also enhances maintainability of the codebase by consolidating similar functionality into a single, more robust implementation approach.