openssl_encrypt before 1.4.9 GPG Signature Verification Bypass

openssl_encrypt versions before 1.4.9 contain a signature verification vulnerability in gpg_runner.verify_detached that accepts revoked and expired keys by only checking VALIDSIG status without inspecting REVKEYSIG, EXPKEYSIG, or gpg exit codes. Attackers holding compromised-then-revoked signing keys or expired project keys can bypass signature verification to execute malicious plugins in the host process.