# CVE-2021-43306: Exponential ReDoS in jquery-validation

> An attacker can cause a denial of service by supplying malicious input to the url2 method in the jquery-validation library.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/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:** Yes
- **Published:** 1 Jun 2022
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-j9m2-h2pv-wvph, UBUNTU-CVE-2021-43306

## What is CVE-2021-43306?

CVE-2021-43306 is a medium-severity denial of service vulnerability in jquery-validation, published on 1 Jun 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An exponential ReDoS (Regular Expression Denial of Service) can be triggered in the jquery-validation npm package, when an attacker is able to supply arbitrary input to the url2 method

Weakness: CWE-1333 (Inefficient Regular Expression Complexity)

## Which versions are affected by CVE-2021-43306?

2 open source packages ship an affected version, including jquery-validation. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `jquery-validation` | npm | All versions | 1.19.4 |
| `jquery-validation` | npm | All versions | 1.19.4 |

Products: Jqueryvalidation Jquery Validation.

## How do I fix CVE-2021-43306?

Upgrade jquery-validation to 1.19.4 or later.

## Is CVE-2021-43306 being exploited?

There is no known exploitation of CVE-2021-43306 in the wild and no public exploit code.

## Other vulnerabilities in jquery-validation

- [CVE-2022-31147](https://insights.sbomify.com/CVE-2022-31147/): jquery-validation ReDoS in url2 due to incomplete fix of CVE-2021-43306 (high 7.5)
- [CVE-2021-21252](https://insights.sbomify.com/CVE-2021-21252/): Regular expression denial of service in jquery-validation (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-43306 and fix it if it is affected.

What it is: CVE-2021-43306 is a medium-severity denial of service vulnerability in jquery-validation, published on 1 Jun 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-2021-43306 in the wild and no public exploit code.

Affected packages and fixed versions:
- jquery-validation (npm): affected all versions; fixed in 1.19.4
- jquery-validation (npm): affected all versions; fixed in 1.19.4

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-2021-43306/ (Markdown: https://insights.sbomify.com/CVE-2021-43306/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-43306
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-43306
- OSV: https://osv.dev/vulnerability/CVE-2021-43306

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-43306/
Summaries are generated and may contain mistakes; the official description above is the record.