# CVE-2026-14957: FIPS mode assertion failure via malicious CERT payload

> Remote attackers can crash the Libreswan daemon by sending malformed certificates in FIPS mode, causing a denial of service.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 2 Sep 2026
- **Updated:** 2 Sep 2026
- **Also known as:** AZL-98441, CLSA-2026-1785422092, CLSA-2026-1785496521, DEBIAN-CVE-2026-14957, GHSA-x2hf-3rgr-r89x, MGASA-2026-0456, OESA-2026-3299, UBUNTU-CVE-2026-14957

## What is CVE-2026-14957?

CVE-2026-14957 is a high-severity denial of service vulnerability in The Libreswan Project libreswan, published on 2 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-617 (Reachable Assertion), CWE-252 (Unchecked Return Value)

## Which versions are affected by CVE-2026-14957?


## How do I fix CVE-2026-14957?

Apply the vendor's patch.

## Is CVE-2026-14957 being exploited?

There is no known exploitation of CVE-2026-14957 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-14957 and fix it if it is affected.

What it is: CVE-2026-14957 is a high-severity denial of service vulnerability in The Libreswan Project libreswan, published on 2 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-14957 in the wild and no public exploit code.

Affected product: The Libreswan Project libreswan. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-14957/ (Markdown: https://insights.sbomify.com/CVE-2026-14957/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-14957
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-14957
- OSV: https://osv.dev/vulnerability/CVE-2026-14957

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-14957/
Summaries are generated and may contain mistakes; the official description above is the record.