CMS (Cryptographic Message Syntax) parsing in gpgsm in GnuPG through 2.5.20 mishandles the CMS format for AES-GCM because aes-ICVlen is supposed to be 12 bytes but 4 bytes is accepted. NOTE: this is related to CVE-2026-34182.Referenceshttps://blog.calif.io/p/how-to-format-a-ciphertexthttps://www.gnupg.org/download/
