CVE-2026-68125

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.