CVE-2025-38512 Information

Aug 17, 2025 cve

Description

In the Linux kernel the following vulnerability has been resolved:

wifi: prevent A-MSDU attacks in mesh networks

This patch is a mitigation to prevent the A-MSDU spoofing vulnerability for mesh networks. The initial update to the IEEE 802.11 standard in response to the FragAttacks missed this case (CVE-2025-27558). It can be considered a variant of CVE-2020-24588 but for mesh networks.

This patch tries to detect if a standard MSDU was turned into an A-MSDU by an adversary. This is done by parsing a received A-MSDU as a standard MSDU calculating the length of the Mesh Control header and seeing if the 6 bytes after this header equal the start of an rfc1042 header. If equal this is a strong indication of an ongoing attack attempt.

This defense was tested with mac80211_hwsim against a mesh network that uses an empty Mesh Address Extension field i.e. when four addresses are used and when using a 12-byte Mesh Address Extension field i.e. when six addresses are used. Functionality of normal MSDUs and A-MSDUs was also tested and confirmed working when using both an empty and 12-byte Mesh Address Extension field.

It was also tested with mac80211_hwsim that A-MSDU attacks in non-mesh networks keep being detected and prevented.

Note that the vulnerability being patched and the defense being implemented was also discussed in the following paper and in the following IEEE 802.11 presentation:

https://papers.mathyvanhoef.com/wisec2025.pdf https://mentor.ieee.org/802.11/dcn/25/11-25-0949-00-000m-a-msdu-mesh-spoof-protection.docx

Reference

https://git.kernel.org/stable/c/6e3b09402cc6c3e3474fa548e8adf6897dda05de https://git.kernel.org/stable/c/737bb912ebbe4571195c56eba557c4d7315b26fb https://git.kernel.org/stable/c/e01851f6e9a665a6011b14714b271d3e6b0b8d32 https://git.kernel.org/stable/c/e2c8a3c0388aef6bfc4aabfba07bc7dff16eea80 https://git.kernel.org/stable/c/ec6392061de6681148b63ee6c8744da833498cdd

CNNVD-202508-1932 (Published: 2025-08-16)

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