CVE-2026-14957

Summary

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.

Affected Software

Weaknesses

• CWE-617: CWE-617: Reachable Assertion
• CWE-252: CWE-252: Unchecked Return Value

Workarounds

No workaround is available unless one is willing to disable FIPS mode. If libreswan is only using PreSharedKey (PSK) authentication and the NSS database contains no CA certificates, CERT payloads are ignored and libreswan is not vulnerable.

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: yes
  • Technical Impact: partial

References

• https://libreswan.org/security/CVE-2026-14957/CVE-2026-14957.txt
• https://libreswan.org/security/CVE-2026-14957/

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