# CVE-2026-20222: Denial of service in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software

> An unauthenticated adjacent attacker can cause a denial of service by sending crafted EIGRP updates, triggering a memory leak and device reload.

- **Severity:** High 7.4 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 16 Sep 2026
- **Updated:** 18 Sep 2026
- **Also known as:** GHSA-3p99-hh66-cfh4

## What is CVE-2026-20222?

CVE-2026-20222 is a high-severity denial of service vulnerability in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, published on 16 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability in the EIGRP implementation in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, adjacent attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition.

This vulnerability is due to improper resource management when handling EIGRP update messages. An attacker could exploit this vulnerability by sending crafted EIGRP updates at a high rate to an affected device. A successful exploit could allow the attacker to trigger a memory leak that will eventually cause the affected device to reload unexpectedly.

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2026-20222?


## How do I fix CVE-2026-20222?

No fix has been published for CVE-2026-20222 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-20222 being exploited?

There is no known exploitation of CVE-2026-20222 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-20222 and fix it if it is affected.

What it is: CVE-2026-20222 is a high-severity denial of service vulnerability in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, published on 16 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-20222 in the wild and no public exploit code.

Affected product: Cisco Secure Firewall Adaptive Security Appliance (ASA) Software. 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-2026-20222/ (Markdown: https://insights.sbomify.com/CVE-2026-20222/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-20222
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-20222
- OSV: https://osv.dev/vulnerability/CVE-2026-20222

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-20222/
Summaries are generated and may contain mistakes; the official description above is the record.