RUSTSEC-2026-0211None▾ SunlitNon-constant time Authentication Tag Check in AES-GCM Decryption
▾ Sunlit zone — Low / medium · no exploitation signal
impact 2.8 · likelihood 0 · exploitation 0
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Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via OSV
Last analysed / modified upstream
AES-GCM decryption used an implementation for checking the provided
authentication tag against the recomputed authentication tag that was
intended to be constant-time, but resulted in non-constant-time code
generation in certain circumstances.
Note that libcrux-aesgcm does not give guarantees on constant-time
code generation and possible mitigations must be considered
on a best-effort basis.
Users of libcrux-aesgcm that expose a decryption oracle to an
attacker, which allows repeatedly querying for the same ciphertext
were at risk from timing side-channel attacks, depending on their
compilation environment. In the worst case, this could lead to
recovery of the recomputed authentication tag by the attacker, which
enables ciphertext forgery.
Starting from version 0.0.9 (published as [email protected]),
AES-GCM decryption uses a different, best-effort constant-time
implementation of the tag check, which has been checked to reliably
lead to constant time code generation, at the moment.
libcrux-aesgcm >= 0.0.0-0Refer to the advisory for the patched release.
Connected by shared product, vendor, weakness, or advisory.