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.
CVSS Details
- CVSS 3.1 Base Score: 7.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade libreswan | Jul 27, 2026 | Jul 27, 2026 |
| Alpine Linux | — | Upgrade libreswan | Sep 28, 2026 | Sep 2, 2026 |
| Redhat Openshift | — | Upgrade rhcos | Sep 11, 2026 | Jul 15, 2026 |
| Redhat_linux | — | Upgrade libreswan-minimal-debuginfoUpgrade libreswan-minimalUpgrade libreswan-debugsourceNo solution existsUpgrade libreswan-debuginfoUpgrade libreswan | Jul 20, 2026 | Jul 15, 2026 |
| Rocky_linux | — | Upgrade libreswan-debugsourceUpgrade libreswanUpgrade libreswan-debuginfo | Jul 29, 2026 | Jul 27, 2026 |
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