CVE-2026-57062

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.

• gnupg2 2.4.9-5 [trixie] - gnupg2 (Minor issue) [bookworm] - gnupg2 (Minor issue) [bullseye] - gnupg2 (gpgsm GCM CMS-decrypt path not present; introduced after 2.2.27) https://blog.calif.io/p/how-to-format-a-ciphertext Fixed by: https://github.com/gpg/gnupg/commit/4c7e68cf3d335328821bdbb70db309a60d0e4fd4