CVE-2026-34182

A flaw was found in OpenSSL's Cryptographic Message Services (CMS) AuthEnvelopedData processing. An on-path attacker can exploit insufficient input validation on cipher and tag length fields by sending specially crafted CMS messages. This can lead to the forging of messages or bypassing integrity validation. Consequently, an attacker may achieve key-equivalent functionality for a given CMS recipient.

Moderate: This flaw in OpenSSL's Cryptographic Message Services (CMS) AuthEnvelopedData processing could allow an on-path attacker to forge messages or bypass integrity validation. This is due to insufficient input validation on cipher and tag length fields, potentially leading to key-equivalent functionality or integrity bypass in applications utilizing affected OpenSSL versions for CMS AuthEnvelopedData.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Systems configured to operate in FIPS mode are not affected by this vulnerability. To mitigate this issue, ensure that OpenSSL is operating in FIPS mode by enabling the system-wide FIPS policy. This may have broader implications for cryptographic operations on the system and should be evaluated for compatibility with existing applications. A system reboot may be required for the changes to take effect.