CVE-2026-68125mac802154: llsec: reject frames shorter than the authentication tag

Official description

In the Linux kernel, the following vulnerability has been resolved: mac802154: llsec: reject frames shorter than the authentication tag llsec_do_decrypt_auth() computes the associated-data length for the AEAD request as assoclen += datalen - authlen; where datalen is the number of bytes after the MAC header and authlen (4, 8 or 16) is the length of the authentication tag. Nothing verifies that the frame actually carries at least authlen payload bytes. A secured frame whose payload is shorter than the tag makes datalen - authlen negative; assoclen is then passed to aead_request_set_ad() as an unsigned value close to 4 GiB, so crypto_aead_decrypt() walks far off the end of the scatterlist that only spans the real frame. The frame is fully attacker-controlled and reaches this path from any IEEE 802.15.4 peer in radio range. Reject frames whose payload is shorter than the authentication tag before the subtraction. Dynamically reproduced on a KASAN kernel as a general-protection-fault in the AEAD scatterwalk, and the fix confirmed.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/f27ce82eb04960465df71634b196a48a4ecafd50
• https://git.kernel.org/stable/c/2d6b42a61373144298070668fddf06efe79cf2ff
• https://git.kernel.org/stable/c/ec7e62d77193131227df49d654d118fdf5a59892
• https://git.kernel.org/stable/c/5bbf0cd9b6a7076af86c75e87e180099be2e11ae
• https://git.kernel.org/stable/c/de80808f37d99c6dc67bb6f97eea00c8f57a8821
• https://git.kernel.org/stable/c/f20dedce0429b293d4bad604e0d3f65d8ac96c83
• https://git.kernel.org/stable/c/e09e0301d616c1ef38a5e64e8e4326fd39df13cc
• https://git.kernel.org/stable/c/fd3a3f28ed60c6af4b2a39933b151d6b27842c3b