Service hang via exponential URL regex backtracking
Published Dec 23, 2022 · Updated Apr 14, 2025
ReDoS in is.js 0.9.0 and earlier allows remote attackers to hang a consuming process through a crafted URL submitted for validation. The is.url function applies an ambiguous URL-validation regular expression to attacker-controlled text, causing exponential backtracking. Exposure requires an application to pass remotely supplied text into is.url; the resulting CPU exhaustion can stall that application's process.
Summary
What happened
ReDoS in is.js 0.9.0 and earlier allows remote attackers to hang a consuming process through a crafted URL submitted for validation. The is.url function applies an ambiguous URL-validation regular expression to attacker-controlled text, causing exponential backtracking. Exposure requires an application to pass remotely supplied text into is.url; the resulting CPU exhaustion can stall that application's process.
The record
- CVE
- CVE-2020-26302
- Published
- Dec 23, 2022
- Updated
- Apr 14, 2025
- Vendor
- Aras Atasaygin
- Product
- is.js
- Classifications
- CWE-400, CWE-1333, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 23, 2022CVE publishedPublication date reported by the CVE source.
- Apr 14, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0.9.0 <=0.9.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GitHub Security Lab is.js ReDoS proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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