Service interruption via exponential regex backtracking
Published Sep 15, 2021 · Updated Aug 3, 2024
Regular expression denial of service in Sindre Sorhus semver-regex before 3.1.3 and 4.0.0 allows remote attackers to interrupt services. The semverRegex function applies an unbounded, ambiguous pattern to crafted semantic-version text, causing exponential backtracking and excessive CPU use. Reachability requires a consuming application to pass attacker-controlled input to the returned regular expression; the consequence is processing delay or service unavailability, although the maintainer disputes treating ReDoS as a package vulnerability.
Summary
What happened
Regular expression denial of service in Sindre Sorhus semver-regex before 3.1.3 and 4.0.0 allows remote attackers to interrupt services. The semverRegex function applies an unbounded, ambiguous pattern to crafted semantic-version text, causing exponential backtracking and excessive CPU use. Reachability requires a consuming application to pass attacker-controlled input to the returned regular expression; the consequence is processing delay or service unavailability, although the maintainer disputes treating ReDoS as a package vulnerability.
The record
- CVE
- CVE-2021-3795
- Published
- Sep 15, 2021
- Updated
- Aug 3, 2024
- Vendor
- Sindre Sorhus
- Product
- semver-regex
- Classifications
- CWE-1333, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 15, 2021CVE publishedPublication date reported by the CVE source.
- Aug 3, 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=unspecified <3.1.3
- Affected versionversion=unspecified <4.0.1
What conditions does exploitation require?
What is affected?
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
- Snyk semver-regex ReDoS proof of conceptproof of concept · unverified
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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