CVE-2020-26302

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2022-12-22 · updated 2026-06-17
Weakness: CWE-400

Description

is.js is a general-purpose check library. Versions 0.9.0 and prior contain one or more regular expressions that are vulnerable to Regular Expression Denial of Service (ReDoS). is.js uses a regex copy-pasted from a gist to validate URLs. Trying to validate a malicious string can cause the regex to loop “forever." This vulnerability was found using a CodeQL query which identifies inefficient regular expressions. is.js has no patch for this issue.

Affected products

arasatasaygin is.js: through 0.9.0

References

https://github.com/arasatasaygin/is.js/issues/320
https://securitylab.github.com/advisories/GHSL-2020-295-redos-is.js
https://github.com/arasatasaygin/is.js/issues/320
https://securitylab.github.com/advisories/GHSL-2020-295-redos-is.js

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