CVE-2026-24881: GnuPG: GnuPG: Remote code execution and denial of service via crafted CMS EnvelopedData message

Severity: Critical

CVSS Score: 8.1

In GnuPG before 2.5.17, a crafted CMS (S/MIME) EnvelopedData message carrying an oversized wrapped session key can cause a stack-based buffer overflow in gpg-agent during PKDECRYPT--kem=CMS handling. This can easily be leveraged for denial of service; however, there is also memory corruption that could lead to remote code execution.