High [CVE-2026-14957] badly formatted X.509 certificate can cause an assertion failure that crashes the daemon process
This high-severity Red Hat Linux advisory covers CVE-2026-14957 affecting Fast Datapath for Red Hat Enterprise Linux 9, Red Hat Enterprise Linux 10.0 Extended Update Support, Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.
VulniPulse record published Record updated
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. A flaw was found in Libreswan.
An unauthenticated remote attacker can send a specially crafted X.509 certificate payload during an IKEv1 or IKEv2 exchange. This flaw occurs when Libreswan is operating in FIPS (Federal Information Processing Standards) mode and processing a certificate with an invalid public key, such as an RSA exponent of zero.
This can trigger an assertion failure, leading to the termination of the daemon process and a denial of service.
Is CVE-2026-14957 exploited?
No exploitation is reported in the sources VulniPulse tracks: CVE-2026-14957 is not in the CISA KEV catalog (checked ) and this advisory does not report exploitation. That is not proof the vulnerability cannot be exploited.
How do I fix CVE-2026-14957?
Upgrade to a fixed release named by Red Hat:
- libreswan-0:5.3.2-1.el9fdp
- libreswan-0:5.3.2-1.el10_2
- libreswan-0:5.2-1.el10_0.5
- libreswan-0:4.12-2.el8_10.6
- libreswan-0:4.3-6.el8_4.2
- libreswan-0:4.5-1.el8_6.6
- libreswan-0:4.9-3.el8_8.3
- libreswan-0:4.15-10.el9_8
- libreswan-0:4.9-5.el9_2.5
- libreswan-0:4.12-3.el9_4.2
- libreswan-0:4.15-8.el9_6.1
- openshift/ose-rhel-coreos-9:4.19.9.6.202609021231-0
16 more fixed releases are listed below.
Confirm against the vendor advisory before you patch.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.
Official advisory · high-confidence parse· fetched 6 days ago·verify at source
- libreswan-0:5.3.2-1.el9fdp
- libreswan-0:5.3.2-1.el10_2
- libreswan-0:5.2-1.el10_0.5
- libreswan-0:4.12-2.el8_10.6
- libreswan-0:4.3-6.el8_4.2
- libreswan-0:4.5-1.el8_6.6
- libreswan-0:4.9-3.el8_8.3
- libreswan-0:4.15-10.el9_8
- libreswan-0:4.9-5.el9_2.5
- libreswan-0:4.12-3.el9_4.2
- libreswan-0:4.15-8.el9_6.1
- openshift/ose-rhel-coreos-9:4.19.9.6.202609021231-0
- openshift/ose-rhel-coreos-9:4.20.9.6.202609021029-0
- openshift/ose-rhel-coreos-9:4.21.9.6.202609021100-0
- RHSA-2026:46986
- RHSA-2026:46398
- RHSA-2026:55449
- RHSA-2026:46396
- RHSA-2026:84887
- RHSA-2026:82154
- RHSA-2026:72287
- RHSA-2026:46397
- RHSA-2026:61779
- RHSA-2026:61258
- RHSA-2026:57741
- RHSA-2026:63044
- RHSA-2026:63100
- RHSA-2026:63041
Official advisory · high-confidence parse· fetched 6 days ago·verify at source
Mitigation checklist
- No mitigation is currently available that meets Red Hat Product Security's standards for usability, deployment, applicability, or stability. Customers are advised to apply the appropriate security updates once they become available.
Official advisory · high-confidence parse· fetched 6 days ago·verify at source
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