CVE-2026-42764

/// Technical description

Issue summary: Receiving a QUIC initial packet with an invalid token may

trigger a NULL pointer dereference in the OpenSSL QUIC server with

address validation disabled.

Impact summary: NULL pointer dereference typically causes abnormal termination

of the affected QUIC server process and a Denial of Service.

If the address validation is disabled in the OpenSSL QUIC server

implementation, an attacker can crash the server by sending an initial

packet with an invalid or expired token.

By default, the client address validation is enabled in the OpenSSL QUIC server

implementation, which makes the default configuration not vulnerable

to this issue. However if the SSL_LISTENER_FLAG_NO_VALIDATE is used with

the SSL_new_listener() call, the address validation is disabled making the

vulnerable code reachable.

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