CVE-2026-87732

An issue was discovered in the mirage-crypto package before 2.2.0 for OCaml. The AES.GCM.authenticate_decrypt_into and Chacha20.authenticate_decrypt_into functions write the decrypted plaintext into a caller-provided buffer and only then compares the tag. On a forged tag, the functions returns false, but the destination buffer already holds the full plaintext.