Application hang via exponential strict-mode regex backtracking
Published Mar 12, 2021 · Updated Aug 3, 2024
Regular expression denial of service in npm ssri 5.2.2 through 6.0.1 and 7.0.0 through 8.0.0 allows attackers to hang applications via malicious SRIs. The STRICT_SRI_REGEX in index.js applies a repeated optional suffix group to attacker-controlled question marks, causing exponential backtracking when a trailing byte falls outside the accepted range. The vulnerable path is reached only when a consuming application enables the non-default strict option; processing can monopolize the JavaScript event loop and hang that application.
Summary
What happened
Regular expression denial of service in npm ssri 5.2.2 through 6.0.1 and 7.0.0 through 8.0.0 allows attackers to hang applications via malicious SRIs. The STRICT_SRI_REGEX in index.js applies a repeated optional suffix group to attacker-controlled question marks, causing exponential backtracking when a trailing byte falls outside the accepted range. The vulnerable path is reached only when a consuming application enables the non-default strict option; processing can monopolize the JavaScript event loop and hang that application.
The record
- CVE
- CVE-2021-27290
- Published
- Mar 12, 2021
- Updated
- Aug 3, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-400, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 12, 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?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
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
- Strict-mode malicious SRI proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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