# CVE-2026-12413: IKEv2 Denial of Service via malformed fragmentation

> Remote attackers can crash the Libreswan pluto daemon by sending malformed IKEv2 fragments, 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 Jul 2026
- **Updated:** 7 Jul 2026
- **Also known as:** AZL-91779, CLSA-2026-1784019530, CLSA-2026-1784075638, DEBIAN-CVE-2026-12413, GHSA-vj68-68x2-jwjq, UBUNTU-CVE-2026-12413

## What is CVE-2026-12413?

CVE-2026-12413 is a high-severity denial of service vulnerability in The Libreswan Project libreswan, published on 2 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An invalidly formatted IKEv2 fragment causes the Libreswan pluto daemon to crash and restart. Continued exploitation would cause a denial of service. The function reassemble_v2_incoming_fragments() would ignore unknown outer payloads but still store these in a fixed size array msg_digest.digest[PAYLIMIT]. An off-by-one error in the assertion PASSERT(logger, md->digest_roof < elemsof(md->digest)) causes the daemon to abort. No remote code execution is possible. Any configuration that allows IKEv2 connections that do not set fragmentation=no are vulnerable. IKEv1 is not affected.

Weakness: CWE-617 (Reachable Assertion), CWE-193 (Off-by-one Error)

## Which versions are affected by CVE-2026-12413?

It affects 1 product.


Products: Libreswan Libreswan.

## How do I fix CVE-2026-12413?

Apply the vendor's patch.

## Is CVE-2026-12413 being exploited?

There is no known exploitation of CVE-2026-12413 in the wild and no public exploit code.

## Other vulnerabilities in The Libreswan Project libreswan

- [CVE-2013-7283](https://insights.sbomify.com/CVE-2013-7283/): Race condition in n/a (critical 9.3)
- [CVE-2026-50721](https://insights.sbomify.com/CVE-2026-50721/): IKEv1 Denial of Service via RSA-SHA1 (PKCS#1 Version 1.5 Encrypted) authentication payload (high 7.5)
- [CVE-2026-50722](https://insights.sbomify.com/CVE-2026-50722/): IKEv2 Denial of Service via RSA-SHA1 (PKCS#1 RSASSA-PKCS1-v1_5) authentication payload (high 7.5)
- [CVE-2023-30570](https://insights.sbomify.com/CVE-2023-30570/): Denial of service in n/a (high 7.5)
- [CVE-2023-2295](https://insights.sbomify.com/CVE-2023-2295/): Denial of service in libreswan (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-12413 and fix it if it is affected.

What it is: CVE-2026-12413 is a high-severity denial of service vulnerability in The Libreswan Project libreswan, published on 2 Jul 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-2026-12413 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-2026-12413/ (Markdown: https://insights.sbomify.com/CVE-2026-12413/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-12413
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-12413
- OSV: https://osv.dev/vulnerability/CVE-2026-12413

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-12413/
Summaries are generated and may contain mistakes; the official description above is the record.