# CVE-2022-20943: Denial of service in Cisco Cyber Vision

> Unauthenticated remote attackers can cause a denial of service or bypass security policies by sending high-rate SMB2 packets to Cisco devices using Snort 3.

- **Severity:** Medium 5.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Nov 2022
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-wfgx-7r85-fvqv

## What is CVE-2022-20943?

CVE-2022-20943 is a medium-severity denial of service vulnerability in Cisco Secure Firewall Threat Defense, published on 10 Nov 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Multiple vulnerabilities in the Server Message Block Version 2 (SMB2) processor of the Snort detection engine on multiple Cisco products could allow an unauthenticated, remote attacker to bypass the configured policies or cause a denial of service (DoS) condition on an affected device.

 These vulnerabilities are due to improper management of system resources when the Snort detection engine is processing SMB2 traffic. An attacker could exploit these vulnerabilities by sending a high rate of certain types of SMB2 packets through an affected device. A successful exploit could allow the attacker to trigger a reload of the Snort process, resulting in a DoS condition.

 Note: When the snort preserve-connection option is enabled for the Snort detection engine, a successful exploit could also allow the attacker to bypass the configured policies and deliver a malicious payload to the protected network. The snort preserve-connection setting is enabled by default. See the Details ["#details"] section of this advisory for more information.

 Note: Only products that have Snort 3 configured are affected. Products that are configured with Snort 2 are not affected.

Weakness: CWE-244 (Improper Clearing of Heap Memory Before Release)

## Which versions are affected by CVE-2022-20943?

It affects 3 products.


Products: Cisco Cyber Vision, Cisco Meraki Mx Security Appliance Firmware, Cisco Secure Firewall Threat Defense.

## How do I fix CVE-2022-20943?

No fix has been published for CVE-2022-20943 yet. Limit exposure of the affected software until one is available.

## Is CVE-2022-20943 being exploited?

There is no known exploitation of CVE-2022-20943 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Secure Firewall Threat Defense

- [CVE-2022-20685](https://insights.sbomify.com/CVE-2022-20685/): Multiple Cisco Products Snort Modbus Denial of Service Vulnerability (high 7.5)
- [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)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-20943 and fix it if it is affected.

What it is: CVE-2022-20943 is a medium-severity denial of service vulnerability in Cisco Secure Firewall Threat Defense, published on 10 Nov 2022. 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-2022-20943 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-2022-20943/ (Markdown: https://insights.sbomify.com/CVE-2022-20943/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-20943
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-20943
- OSV: https://osv.dev/vulnerability/CVE-2022-20943

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From sbomify Insights: https://insights.sbomify.com/CVE-2022-20943/
Summaries are generated and may contain mistakes; the official description above is the record.