CVE-2026-14957 FIPS mode assertion failure via malicious CERT payload
Remote attackers can crash the Libreswan daemon by sending malformed certificates in FIPS mode, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-14957?
CVE-2026-14957 is a high-severity denial of service vulnerability in The Libreswan Project libreswan, published on 2 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In FIPS mode, Libreswan's add_decoded_cert() function calls CERT_ExtractPublicKey() and asserts that the result is not NULL. However, CERT_ExtractPublicKey() returns NULL when public key extraction fails, for example if the RSA exponent is set to 0. A remote attacker can send a malformed X.509 certificate in a CERT payload to trigger the assertion, causing the pluto daemon to abort and restart. Continued exploitation causes a denial of service. No remote code execution is possible. Both IKEv1 and IKEv2 are affected. The vulnerability is only exploitable when both the OS and libreswan are running in FIPS mode and at least one CA certificate is loaded. The CERT payload is processed before peer authentication, so no credentials are needed to exploit this. Configurations using only PreSharedKey (PSK) authentication with no CA certificates loaded in the NSS database are not vulnerable.
Which versions are affected by CVE-2026-14957?
How do I fix CVE-2026-14957?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-14957 being exploited?
There is no known exploitation of CVE-2026-14957 in the wild and no public exploit code.
Sources
Also known as AZL-98441, CLSA-2026-1785422092, CLSA-2026-1785496521, DEBIAN-CVE-2026-14957, GHSA-x2hf-3rgr-r89x, MGASA-2026-0456 and 2 more.