# CVE-2021-23495: Open Redirect

> Attackers can redirect users to malicious sites via the return_url parameter in the Karma test runner, potentially facilitating phishing attacks.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 25 Feb 2022
- **Updated:** 16 Sep 2024
- **Also known as:** CLSA-2026-1774657354, CLSA-2026-1791028060, GHSA-rc3x-jf5g-xvc5

## What is CVE-2021-23495?

CVE-2021-23495 is a medium-severity vulnerability in karma, published on 25 Feb 2022. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

The package karma before 6.3.16 are vulnerable to Open Redirect due to missing validation of the return_url query parameter.

Weakness: CWE-601 (URL Redirection to Untrusted Site)

## Which versions are affected by CVE-2021-23495?

2 open source packages ship an affected version, including karma. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `karma` | npm | All versions | 6.3.16 |
| `karma` | npm | All versions | 6.3.16 |

Products: Karma Project Karma.

## How do I fix CVE-2021-23495?

Upgrade karma to 6.3.16 or later.

## Is CVE-2021-23495 being exploited?

There is no known exploitation of CVE-2021-23495 in the wild and no public exploit code.

## Other vulnerabilities in karma

- [CVE-2022-0437](https://insights.sbomify.com/CVE-2022-0437/): Cross-site Scripting (XSS) - DOM in karma-runner/karma (medium 5.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-23495 and fix it if it is affected.

What it is: CVE-2021-23495 is a medium-severity vulnerability in karma, published on 25 Feb 2022. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-23495 in the wild and no public exploit code.

Affected packages and fixed versions:
- karma (npm): affected all versions; fixed in 6.3.16
- karma (npm): affected all versions; fixed in 6.3.16

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-2021-23495/ (Markdown: https://insights.sbomify.com/CVE-2021-23495/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-23495
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-23495
- OSV: https://osv.dev/vulnerability/CVE-2021-23495

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-23495/
Summaries are generated and may contain mistakes; the official description above is the record.