There is a new GnuPG update for a "critical security bug" in recent GnuPG releases. A crafted CMS (S/MIME) EnvelopedData message carrying an oversized wrapped session key can cause a stack buffer overflow in gpg-agent during the PKDECRYPT--kem=CMS handling. This can easily be used for a DoS but, worse, the memory corruption can very likley also be used to mount a remote code execution attack. The bug was introduced while changing an internal API to the FIPS required KEM API. Only versions 2.5.13 through 2.5.16 are affected.