CVE-2025-15468 NULL dereference in SSL_CIPHER_find() function on unknown cipher ID

Medium 5.9 Published 27 Jan 2026 Updated 29 Jan 2026

A NULL pointer dereference in OpenSSL's QUIC implementation allows remote attackers to cause a denial of service via unknown cipher suites.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2025-15468?

CVE-2025-15468 is a medium-severity vulnerability in Openssl Openssl, published on 27 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Issue summary: If an application using the SSL_CIPHER_find() function in a QUIC protocol client or server receives an unknown cipher suite from the peer, a NULL dereference occurs.

Impact summary: A NULL pointer dereference leads to abnormal termination of the running process causing Denial of Service.

Some applications call SSL_CIPHER_find() from the client_hello_cb callback on the cipher ID received from the peer. If this is done with an SSL object implementing the QUIC protocol, NULL pointer dereference will happen if the examined cipher ID is unknown or unsupported.

As it is not very common to call this function in applications using the QUIC protocol and the worst outcome is Denial of Service, the issue was assessed as Low severity.

The vulnerable code was introduced in the 3.2 version with the addition of the QUIC protocol support.

The FIPS modules in 3.6, 3.5, 3.4 and 3.3 are not affected by this issue, as the QUIC implementation is outside the OpenSSL FIPS module boundary.

OpenSSL 3.6, 3.5, 3.4 and 3.3 are vulnerable to this issue.

OpenSSL 3.0, 1.1.1 and 1.0.2 are not affected by this issue.

Weakness: CWE-476

Which versions are affected by CVE-2025-15468?

It affects 1 product.

Products include Openssl Openssl.

How do I fix CVE-2025-15468?

Apply the vendor's patch.

Is CVE-2025-15468 being exploited?

There is no known exploitation of CVE-2025-15468 in the wild and no public exploit code.

All Openssl Openssl vulnerabilities

Sources

Also known as ALPINE-CVE-2025-15468, AZL-75278, BELL-CVE-2025-15468, CLEANSTART-2026-IP06314, DEBIAN-CVE-2025-15468, GHSA-rhx3-fg8p-f9m4 and 4 more.