# CVE-2026-77206: IKEv2 pre-authentication Null Pointer Dereference in EAP code

> A malicious IKE_AUTH packet can trigger a null pointer dereference in Libreswan, causing a daemon crash and denial of service without authentication.

- **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:** 13 Oct 2026
- **Updated:** 16 Oct 2026
- **Also known as:** AZL-108030, DEBIAN-CVE-2026-77206, GHSA-37xg-hvw9-pr82, UBUNTU-CVE-2026-77206

## What is CVE-2026-77206?

CVE-2026-77206 is a high-severity vulnerability in The Libreswan Project libreswan, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Libreswan's IKEv2 state machine has a null pointer dereference bug in the EAP handling code for authentication. As a result of inconsistency within the IKEv2 state machine code, this bug can be triggered by any IKEv2 connection, even if EAP is not configured at all. The error is caused by a fall-through where it incorrectly dereferences ike->sa.st_eap which is NULL. A malicious IKE_AUTH packet can trigger this bug, meaning the peer does not need to be authenticated. The bug results in a crash and restart of the pluto daemon. No remote code execution is possible. Continued exploitation can cause a denial of service.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-77206?


## How do I fix CVE-2026-77206?

Apply the vendor's patch.

## Is CVE-2026-77206 being exploited?

There is no known exploitation of CVE-2026-77206 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-77206 and fix it if it is affected.

What it is: CVE-2026-77206 is a high-severity vulnerability in The Libreswan Project libreswan, published on 13 Oct 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-2026-77206 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-2026-77206/ (Markdown: https://insights.sbomify.com/CVE-2026-77206/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-77206
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-77206
- OSV: https://osv.dev/vulnerability/CVE-2026-77206

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-77206/
Summaries are generated and may contain mistakes; the official description above is the record.