# Inefficient Regular Expression Complexity in chalk/ansi-regex

Advisory record · `GHSA-93q8-gq69-wqmw`

- **Identifiers:** `GHSA-93q8-gq69-wqmw` · `CVE-2021-3807`
- **State:** Confirmed
- **Severity:** CVSS 7.5 High
- **Critical:** No
- **Weakness (CWE):** [CWE-697](https://cwe.mitre.org/data/definitions/697.html) · [CWE-1333](https://cwe.mitre.org/data/definitions/1333.html)
- **Tags:** [Denial of service](https://agentprime.io/advisories/tag/dos.md) · [CWE-697](https://agentprime.io/advisories/tag/cwe-697.md)
- **Published:** 20 Sept 2021
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 20 Sept 2021, 20:20 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `ansi-regex` (npm): affected `>=6.0.0, <6.0.1 || >=5.0.0, <5.0.1 || >=4.0.0, <4.1.1 || >=3.0.0, <3.0.1`; fixed in `6.0.1`, `5.0.1`, `4.1.1`, `3.0.1`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 7.5 High, CVSS 3.0: `CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`, from CNA (@huntrdev)

- **CISA KEV:** Not listed.
- **EPSS:** 0.036, the 89th percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the GitHub Advisory Database, published 20 Sept 2021. New records show when each source confirmed them.

## Sources

- [GitHub Advisory Database: GHSA-93q8-gq69-wqmw](https://github.com/advisories/GHSA-93q8-gq69-wqmw)
- [OSV: GHSA-93q8-gq69-wqmw](https://osv.dev/vulnerability/GHSA-93q8-gq69-wqmw)
- <https://nvd.nist.gov/vuln/detail/CVE-2021-3807>
- <https://github.com/chalk/ansi-regex/issues/38#issuecomment-924086311>
- <https://github.com/chalk/ansi-regex/issues/38#issuecomment-925924774>
- <https://github.com/chalk/ansi-regex/commit/419250fa510bf31b4cc672e76537a64f9332e1f1>
- <https://github.com/chalk/ansi-regex/commit/75a657da7af875b2e2724fd6331bf0a4b23d3c9a>
- <https://github.com/chalk/ansi-regex/commit/8d1d7cdb586269882c4bdc1b7325d0c58c8f76f9>
- <https://github.com/chalk/ansi-regex/commit/c3c0b3f2736b9c01feec0fef33980c43720dcde8>
- <https://app.snyk.io/vuln/SNYK-JS-ANSIREGEX-1583908>
- <https://github.com/chalk/ansi-regex>
- <https://github.com/chalk/ansi-regex/releases/tag/v6.0.1>
- <https://huntr.dev/bounties/5b3cf33b-ede0-4398-9974-800876dfd994>
- <https://security.netapp.com/advisory/ntap-20221014-0002>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-93q8-gq69-wqmw>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-93q8-gq69-wqmw/>. Everything for agents: <https://agentprime.io/llms.txt>.