# CVE-2021-42075: Denial of service in n/a

> An unauthenticated remote attacker can cause file descriptor exhaustion in the Barrier server, leading to denial of service.

- **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:** 8 Nov 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-c58c-q645-27mc

## What is CVE-2021-42075?

CVE-2021-42075 is a high-severity denial of service vulnerability in n/a, published on 8 Nov 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered in Barrier before 2.3.4. The barriers component (aka the server-side implementation of Barrier) does not correctly close file descriptors for established TCP connections. An unauthenticated remote attacker can thus cause file descriptor exhaustion in the server process, leading to denial of service.

Weakness: CWE-772 (Missing Release of Resource after Effective Lifetime)

## Which versions are affected by CVE-2021-42075?

It affects 1 product.


Products: Barrier Project Barrier.

## How do I fix CVE-2021-42075?

No fix has been published for CVE-2021-42075 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-42075 being exploited?

There is no known exploitation of CVE-2021-42075 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2021-42072](https://insights.sbomify.com/CVE-2021-42072/): Auth bypass in n/a (high 8.8)
- [CVE-2021-42073](https://insights.sbomify.com/CVE-2021-42073/): Auth bypass in n/a (high 8.2)
- [CVE-2021-42074](https://insights.sbomify.com/CVE-2021-42074/): Use after free in n/a (high 7.5)
- [CVE-2021-42076](https://insights.sbomify.com/CVE-2021-42076/): Denial of service in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-42075 and fix it if it is affected.

What it is: CVE-2021-42075 is a high-severity denial of service vulnerability in n/a, published on 8 Nov 2021. 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-2021-42075 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-2021-42075/ (Markdown: https://insights.sbomify.com/CVE-2021-42075/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-42075
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-42075
- OSV: https://osv.dev/vulnerability/CVE-2021-42075

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-42075/
Summaries are generated and may contain mistakes; the official description above is the record.