openssl_encrypt before 1.4.9 fails to validate KDF cost parameters in encrypted file metadata and keystore headers, allowing attackers to trigger unbounded memory allocation. Attackers can craft malicious encrypted files declaring arbitrarily large Argon2, scrypt, or balloon KDF parameters to exhaust system memory and crash the process without authentication.
HIGH
Vulnerability intelligence
CVE-2026-81721
CVSS 4.08.7
SeverityHigh
Known exploitedNo
NVD references:
Primary source: NIST National Vulnerability Database