# CVE-2022-20685: Multiple Cisco Products Snort Modbus Denial of Service Vulnerability

> An unauthenticated remote attacker can cause a denial of service by sending crafted Modbus traffic, hanging the Snort process and stopping traffic inspection.

- **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:** No
- **Published:** 15 Nov 2024
- **Updated:** 27 Jan 2025
- **Also known as:** GHSA-5pj6-3hcq-wv78

## What is CVE-2022-20685?

CVE-2022-20685 is a high-severity vulnerability in Cisco Secure Firewall Threat Defense, published on 15 Nov 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the Modbus preprocessor of the Snort detection engine could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.
This vulnerability is due to an integer overflow while processing Modbus traffic. An attacker could exploit this vulnerability by sending crafted Modbus traffic through an affected device. A successful exploit could allow the attacker to cause the Snort process to hang, causing traffic inspection to stop.Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2022-20685?

It affects 3 products.


Products: Cisco Cyber Vision, Cisco Secure Firewall Threat Defense, Cisco Unified Threat Defense Snort Intrusion Prevention System Engine.

## How do I fix CVE-2022-20685?

No fix has been published for CVE-2022-20685 yet. Limit exposure of the affected software until one is available.

## Is CVE-2022-20685 being exploited?

There is no known exploitation of CVE-2022-20685 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Secure Firewall Threat Defense

- [CVE-2026-20005](https://insights.sbomify.com/CVE-2026-20005/): Denial of service in Cisco Cyber Vision (medium 5.8)
- [CVE-2026-20053](https://insights.sbomify.com/CVE-2026-20053/): Memory corruption in Cisco Cyber Vision (medium 5.8)
- [CVE-2026-20054](https://insights.sbomify.com/CVE-2026-20054/): Denial of service in Cisco Cyber Vision (medium 5.8)
- [CVE-2026-20057](https://insights.sbomify.com/CVE-2026-20057/): Cisco Secure Firewall Threat Defense Software Snort 3 Visual Basic for Application Denial of Service Vulnerability (medium 5.8)
- [CVE-2026-20067](https://insights.sbomify.com/CVE-2026-20067/): Multiple Cisco Products Snort 3 TBD Denial of Service Vulnerability (medium 5.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-20685 and fix it if it is affected.

What it is: CVE-2022-20685 is a high-severity vulnerability in Cisco Secure Firewall Threat Defense, published on 15 Nov 2024. 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-2022-20685 in the wild and no public exploit code.

Affected product: Cisco Secure Firewall Threat Defense. 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-2022-20685/ (Markdown: https://insights.sbomify.com/CVE-2022-20685/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-20685
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-20685
- OSV: https://osv.dev/vulnerability/CVE-2022-20685

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From sbomify Insights: https://insights.sbomify.com/CVE-2022-20685/
Summaries are generated and may contain mistakes; the official description above is the record.