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.

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Advisories

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Fixes

Solution

Upgrade to libreswan 5.3.2 or later. Patches for libreswan 4.15 and 5.3 are available at https://libreswan.org/security/CVE-2026-14957/


Workaround

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.

History

Wed, 02 Sep 2026 02:45:00 +0000

Type Values Removed Values Added
Description No description is available for this CVE. 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.
Title libreswan: badly formatted X.509 certificate can cause an assertion failure that crashes the daemon process FIPS mode assertion failure via malicious CERT payload
Weaknesses CWE-252

Tue, 21 Jul 2026 21:00:00 +0000

Type Values Removed Values Added
First Time appeared Libreswan
Libreswan libreswan
Vendors & Products Libreswan
Libreswan libreswan

Sat, 18 Jul 2026 12:15:00 +0000

Type Values Removed Values Added
Description No description is available for this CVE.
Title libreswan: badly formatted X.509 certificate can cause an assertion failure that crashes the daemon process
Weaknesses CWE-617
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: libreswan

Published:

Updated: 2026-09-02T02:19:00.114Z

Reserved: 2026-07-07T13:39:23.932Z

Link: CVE-2026-14957

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-07-15T00:00:00Z

Links: CVE-2026-14957 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-07-30T00:45:09Z

Weaknesses