CVE-2026-42764

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.

How to fix CVE-2026-42764

To remediate CVE-2026-42764, upgrade the affected package to a fixed version below.

• —upgrade to 3.5.7-r0 or later
• —upgrade to 3.5.6-1~deb13u2 or later

Is CVE-2026-42764 being exploited?

No exploitation signal available. Neither CISA KEV nor a current EPSS score has been published for CVE-2026-42764.

Affected packages (2)

• from 0, < 3.5.7-r0
• from 0, < 3.5.6-1~deb13u2

CVSS scores

References (2)

• ADVISORYsecurity.alpinelinux.org/vuln/CVE-2026-42764
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2026-42764