# CVE-2021-40894: Denial of service in n/a

> An attacker can cause a denial of service in applications using underscore-99xp by triggering a Regular Expression Denial of Service in the deepValueSearch function.

- **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:** 24 Jun 2022
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-2wj2-6jqv-cwpp

## What is CVE-2021-40894?

CVE-2021-40894 is a high-severity denial of service vulnerability in n/a, published on 24 Jun 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A Regular Expression Denial of Service (ReDOS) vulnerability was discovered in underscore-99xp v1.7.2 when the deepValueSearch function is called.

Weakness: CWE-1333 (Inefficient Regular Expression Complexity)

## Which versions are affected by CVE-2021-40894?

It affects 1 product.


Products: Underscore-99xp Project Underscore-99xp.

## How do I fix CVE-2021-40894?

No fix has been published for CVE-2021-40894 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-40894 being exploited?

There is no known exploitation of CVE-2021-40894 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-40894 and fix it if it is affected.

What it is: CVE-2021-40894 is a high-severity denial of service vulnerability in n/a, published on 24 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-2021-40894 in the wild and no public exploit code.

Affected product: n/a. 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-2021-40894/ (Markdown: https://insights.sbomify.com/CVE-2021-40894/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-40894
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-40894
- OSV: https://osv.dev/vulnerability/CVE-2021-40894

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-40894/
Summaries are generated and may contain mistakes; the official description above is the record.