# CVE-2022-20784: Cisco Web Security Appliance Filter Bypass Vulnerability

> Unauthenticated attackers can bypass web proxy policies and access blocked content by sending crafted URLs to Cisco Web Security Appliances.

- **Severity:** Medium 5.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 6 Apr 2022
- **Updated:** 6 Nov 2024
- **Also known as:** GHSA-vv88-544v-pvq3

## What is CVE-2022-20784?

CVE-2022-20784 is a medium-severity vulnerability in Cisco Web Security Appliance, published on 6 Apr 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the Web-Based Reputation Score (WBRS) engine of Cisco AsyncOS Software for Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to bypass established web request policies and access blocked content on an affected device. This vulnerability is due to incorrect handling of certain character combinations inserted into a URL. An attacker could exploit this vulnerability by sending crafted URLs to be processed by an affected device. A successful exploit could allow the attacker to bypass the web proxy and access web content that has been blocked by policy.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2022-20784?

It affects 1 product.


Products: Cisco Web Security Appliance.

## How do I fix CVE-2022-20784?

No fix has been published for CVE-2022-20784 yet. Limit exposure of the affected software until one is available.

## Is CVE-2022-20784 being exploited?

There is no known exploitation of CVE-2022-20784 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Web Security Appliance

- [CVE-2015-6298](https://insights.sbomify.com/CVE-2015-6298/): Command injection in n/a (critical 9.0)
- [CVE-2019-1817](https://insights.sbomify.com/CVE-2019-1817/): Cisco Web Security Appliance Malformed Request Denial of Service Vulnerability (high 8.6)
- [CVE-2018-0410](https://insights.sbomify.com/CVE-2018-0410/): Denial of service in AsyncOS Software for Cisco Web Security Appliances (high 8.6)
- [CVE-2015-6292](https://insights.sbomify.com/CVE-2015-6292/): Denial of service in n/a (high 7.8)
- [CVE-2015-6293](https://insights.sbomify.com/CVE-2015-6293/): Denial of service in n/a (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-20784 and fix it if it is affected.

What it is: CVE-2022-20784 is a medium-severity vulnerability in Cisco Web Security Appliance, published on 6 Apr 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-2022-20784 in the wild and no public exploit code.

Affected product: Cisco Web Security Appliance. 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-2022-20784/ (Markdown: https://insights.sbomify.com/CVE-2022-20784/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-20784
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-20784
- OSV: https://osv.dev/vulnerability/CVE-2022-20784

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-20784/
Summaries are generated and may contain mistakes; the official description above is the record.