Application interruption via catastrophic regex backtracking
Published Jun 8, 2021 · Updated Sep 16, 2024
Regular expression denial of service in Locutus before 2.0.15 allows remote attackers to interrupt applications via crafted Gopher directory data. The gopher_parsedir function matches tab-delimited input with five adjacent lazy wildcard groups, causing catastrophic backtracking on long malformed strings. Exploitation requires a consuming application to pass attacker-controlled data to this function; the resulting CPU exhaustion blocks the hosting JavaScript process.
Summary
What happened
Regular expression denial of service in Locutus before 2.0.15 allows remote attackers to interrupt applications via crafted Gopher directory data. The gopher_parsedir function matches tab-delimited input with five adjacent lazy wildcard groups, causing catastrophic backtracking on long malformed strings. Exploitation requires a consuming application to pass attacker-controlled data to this function; the resulting CPU exhaustion blocks the hosting JavaScript process.
The record
- CVE
- CVE-2021-23392
- Published
- Jun 8, 2021
- Updated
- Sep 16, 2024
- Vendor
- Locutus
- Product
- Locutus
- Classifications
- CWE-400, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 8, 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 <2.0.15
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
- gopher_parsedir ReDoS proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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