CVE-2026-87732: Ocaml Mirage-Crypto

Medium severity, CVSS 6.2. EPSS: 0.1% chance of exploitation in the next 30 days.

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.

Affected products

• Ocaml Mirage-Crypto: before 2.2.0 (fixed in 2.2.0)

Published 2026-09-09. Last modified 2026-09-09.