Service hang via exponential URL-regex backtracking
Published Oct 26, 2024 · Updated Oct 28, 2024
Regular expression denial of service in Knwl.js 1.0.2 and earlier allows remote attackers to interrupt services via crafted link text. The default links plugin tests each candidate word with a URL-validation expression whose overlapping repeated groups trigger exponential backtracking on a long malformed URL. The parser must be embedded in an application that passes attacker-controlled text to the links plugin; processing the input monopolizes CPU and can hang that application.
Summary
What happened
Regular expression denial of service in Knwl.js 1.0.2 and earlier allows remote attackers to interrupt services via crafted link text. The default links plugin tests each candidate word with a URL-validation expression whose overlapping repeated groups trigger exponential backtracking on a long malformed URL. The parser must be embedded in an application that passes attacker-controlled text to the links plugin; processing the input monopolizes CPU and can hang that application.
The record
- CVE
- CVE-2020-26306
- Published
- Oct 26, 2024
- Updated
- Oct 28, 2024
- Vendor
- benhmoore
- Product
- Knwl.js
- Classifications
- CWE-1333, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 26, 2024CVE publishedPublication date reported by the CVE source.
- Oct 28, 2024Record 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 <=1.0.2
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 Node.js proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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