CVE-2026-42769

/// Technical description

Issue Summary: An error in the callback used to verify the certificate

provided in a Root CA key update Certificate Management Protocol (CMP)

message response rendered the certificate validation ineffectual, which

could lead to escalation of credentials from the Registration Authority (RA)

level to the root Certification Authority (root CA) level.

Impact Summary: The Registration Autority could replace the root CA

certificate for the CMP clients with an arbitrary root CA certificate.

One of the parts of the Certificate Management Protocol (CMP), specified in

RFC 9810, is Root Certification Authority (root CA) key Rollover,

which is sent by the server in a message with type 'id-it-rootCaKeyUpdate'.

As part of these messages, 'newWithOld' certificate, the new root CA

certificate signed with the old root CA key, is provided, and verifying its

signature is crucial for transferring the trust from the old CA key to the

new one.

The 'id-it-rootCaKeyUpdate' messages are expected to be proce

/// 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