Service interruption via inefficient whitespace regexes
Published Feb 15, 2021 · Updated Sep 16, 2024
Regular expression denial of service in Lodash before 4.17.21 allows remote attackers to interrupt services via crafted strings. The toNumber, trim, and trimEnd paths apply end-anchored whitespace regular expressions that backtrack across long strings ending in a nonspace. Exploitation requires an application to pass attacker-controlled strings to one of these functions, consuming CPU and delaying the calling process.
Summary
What happened
Regular expression denial of service in Lodash before 4.17.21 allows remote attackers to interrupt services via crafted strings. The toNumber, trim, and trimEnd paths apply end-anchored whitespace regular expressions that backtrack across long strings ending in a nonspace. Exploitation requires an application to pass attacker-controlled strings to one of these functions, consuming CPU and delaying the calling process.
The record
- CVE
- CVE-2020-28500
- Published
- Feb 15, 2021
- Updated
- Sep 16, 2024
- Vendor
- Lodash
- Product
- Lodash
- Classifications
- CWE-1333, CWE-400, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 15, 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=versions prior to 4.17.21
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 Advisory Database reproduction codeproof 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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