Service interruption via unbounded regex parsing
Published Dec 24, 2021 · Updated Sep 16, 2024
Regular expression denial of service in parse-link-header before 2.0.0 allows remote attackers to interrupt services via a crafted Link header. The exported parser accepts an unbounded Link header and runs parsing regular expressions over a malformed rel parameter containing a long whitespace run. An application must pass attacker-controlled Link headers to the library; the resulting CPU consumption blocks parsing and interrupts the hosting process.
Summary
What happened
Regular expression denial of service in parse-link-header before 2.0.0 allows remote attackers to interrupt services via a crafted Link header. The exported parser accepts an unbounded Link header and runs parsing regular expressions over a malformed rel parameter containing a long whitespace run. An application must pass attacker-controlled Link headers to the library; the resulting CPU consumption blocks parsing and interrupts the hosting process.
The record
- CVE
- CVE-2021-23490
- Published
- Dec 24, 2021
- Updated
- Sep 16, 2024
- Vendor
- Thorsten Lorenz
- Product
- parse-link-header
- Classifications
- CWE-1333, CWE-400, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 24, 2021CVE publishedPublication date reported by the CVE source.
- Sep 16, 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 <2.0.0
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 parse-link-header ReDoS proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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