crypto11 Go library <2.0.0-rc9 (>=2.0.0-rc3) MLKEM key pair lookup bypass
CVE-2026-115408 Published on October 27, 2026

ML-KEM key-pair lookup can bind an unrelated or attacker-planted public key, exposing encapsulated shared secrets
In `github.com/eclipse-keypont/crypto11/v2` versions `>= 2.0.0-rc3, <= 2.0.0-rc8`, the ML-KEM key-pair lookup functions (`FindMLKEMKeyPair`, `FindMLKEMKeyPairs`, `FindMLKEMKeyPairsWithAttributes`) locate the public half of an ML-KEM key pair by `CKA_ID`/`CKA_LABEL` and never verify it against the private key. In addition, the "ID only" fallback search runs even when the private key has no `CKA_ID`, so the search template reduces to the public-key class and the ML-KEM key type and the first ML-KEM public key on the token is returned. `Encapsulate()` on the resulting key pair encrypts the fresh shared secret to that key, so its owner not the holder of the private key the caller looked up can recover the secret. An attacker who can open an unauthenticated session on the token and plant a public `CKK_ML_KEM` object carrying the victim's `CKA_ID`/`CKA_LABEL` receives the shared secrets for encapsulations performed through the substituted key pair, compromising the confidentiality of those secrets and of everything protected by keys derived from them. The v1 module paths have no ML-KEM support and are not affected.