CVE-2026-42767

/// Technical description

Issue summary: An attacker-controlled CMP (Certificate Management Protocol)

server could trigger a NULL pointer dereference in a CMP client application.

Impact summary: A NULL pointer dereference causes a crash of the

application and a Denial of Service.

An attacker controlling a CMP server (or acting as a man-in-the-middle) could

craft a CMP response containing a CRMF (Certificate Request Message Format)

CertRepMessage with an EncryptedValue structure where the symmAlg field

has an algorithm OID but no parameters field. When the OpenSSL CMP client

processes this response, the NULL dereference occurs, causing a crash of

the CMP client.

Applications that process untrusted CMP/CRMF messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this

issue, as the affected code is outside the OpenSSL FIPS module boundary.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References