Prototype pollution via non-string path components
Published Sep 12, 2021 · Updated Sep 16, 2024
Prototype pollution in set-value before 2.0.1, 3.0.0 through 3.0.2, and 4.0.0 allows attackers to alter object prototypes via array paths. The path validator compares each component against unsafe names before coercing non-string array elements, so a nested array containing proto evades the comparison and is later converted to the forbidden property name. Exploitation requires a consuming application to pass attacker-controlled array path components; the polluted prototype can change inherited properties throughout that process.
Summary
What happened
Prototype pollution in set-value before 2.0.1, 3.0.0 through 3.0.2, and 4.0.0 allows attackers to alter object prototypes via array paths. The path validator compares each component against unsafe names before coercing non-string array elements, so a nested array containing proto evades the comparison and is later converted to the forbidden property name. Exploitation requires a consuming application to pass attacker-controlled array path components; the polluted prototype can change inherited properties throughout that process.
The record
- CVE
- CVE-2021-23440
- Published
- Sep 12, 2021
- Updated
- Sep 16, 2024
- Vendor
- Jon Schlinkert
- Product
- set-value
- Classifications
- CWE-1321, CWE-843
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 12, 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=<2.0.1
- Affected versionversion=>=3.0.0 <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
- Array-path prototype-pollution regression payloadproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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