A russh SSH server accepts a publickey authentication whose signature uses a different algorithm than the one named in the request

影響: rust:russh >= 0.34.0-beta.1, < 0.64.0 → 0.64.0

In russh/src/server/encrypted.rs, server_read_auth_request_pk (0.63.3, around lines 880-990): The requested algorithm name (pubkey_algo) is read and only used to decode the key: PublicKeyOrCertificate::decode(&pubkey_algo, &pubkey_key). The derived hash_alg is then dropped (PublicKeyOrCertificate::PublicKey { ref key, .. }). The signature blob is decoded (Signature::decode) and verified with Verifier::verify(&pubkey, &buf, &sig). ssh-key picks the hash from the signature's own algorithm…

Read on GitHub Advisory Database

On 10/20/2026, 02:06 AM, GitHub Advisory Database published "A russh SSH server accepts a publickey authentication whose signature uses a different algorithm than the one named in the request" (type: Advisory). Severity is "Low" (low). Related technologies: Rust. CVE: CVE-2026-111062.