CVE-2026-14957

FIPS mode assertion failure via malicious CERT payload

HIGH
7.5
CVSS Score
Published: September 2, 2026 at 02:19 AM UTC
Updated: September 9, 2026 at 05:27 PM UTC
1 product affected across 1 vendorLibreswan

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Severity
HIGH7.5
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

3.0 ≤ v ≤ 5.3.13.0
Vendor states this is fixed in 5.3.2 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHlibreswan
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-617CWE-252

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