# CVE-2022-21195: Regular Expression Denial of Service (ReDoS)

> Attackers can cause CPU exhaustion and service crashes in applications using the url-regex library via crafted input.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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:** 20 May 2022
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-hg3w-7hj9-m3f7

## What is CVE-2022-21195?

CVE-2022-21195 is a medium-severity denial of service vulnerability in url-regex, published on 20 May 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

All versions of package url-regex are vulnerable to Regular Expression Denial of Service (ReDoS) which can cause the CPU usage to crash.

Weakness: CWE-1333 (Inefficient Regular Expression Complexity)

## Which versions are affected by CVE-2022-21195?

2 open source packages ship an affected version, including url-regex and url_regex. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `url-regex` | PyPI | All versions to 1.0.4 | None |
| `url_regex` | PyPI | All versions to 1.0.4 | None |

Products: Url-Regex Project Url-Regex.

## How do I fix CVE-2022-21195?

No fix has been published for CVE-2022-21195 yet. Limit exposure of the affected software until one is available.

## Is CVE-2022-21195 being exploited?

There is no known exploitation of CVE-2022-21195 in the wild and no public exploit code.

## Other vulnerabilities in url-regex

- [CVE-2020-7661](https://insights.sbomify.com/CVE-2020-7661/): Regular expression denial of service in url-regex (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-21195 and fix it if it is affected.

What it is: CVE-2022-21195 is a medium-severity denial of service vulnerability in url-regex, published on 20 May 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-2022-21195 in the wild and no public exploit code.

Affected packages and fixed versions:
- url-regex (PyPI): affected all versions up to 1.0.4; no fix listed
- url_regex (PyPI): affected all versions up to 1.0.4; no fix listed

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-2022-21195/ (Markdown: https://insights.sbomify.com/CVE-2022-21195/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-21195
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-21195
- OSV: https://osv.dev/vulnerability/CVE-2022-21195

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-21195/
Summaries are generated and may contain mistakes; the official description above is the record.