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.
References
History

Wed, 09 Sep 2026 14:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 09 Sep 2026 11:45:00 +0000

Type Values Removed Values Added
Title Potential Plaintext Exposure from Forged Tag in Mirage-Crypto AES/GCM and ChaCha20 Decrypt Functions

Wed, 09 Sep 2026 04:30:00 +0000

Type Values Removed Values Added
Description 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.
Weaknesses CWE-347
References
Metrics cvssV3_1

{'score': 6.2, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published: 2026-09-09T04:03:53.056Z

Updated: 2026-09-09T13:11:54.773Z

Reserved: 2026-09-09T04:03:52.629Z

Link: CVE-2026-87732

cve-icon Vulnrichment

Updated: 2026-09-09T13:11:51.667Z

cve-icon NVD

Status : Deferred

Published: 2026-09-09T05:18:20.277

Modified: 2026-09-09T16:04:24.933

Link: CVE-2026-87732

cve-icon Redhat

No data.