Object prototype modification via unchecked property paths
Published Aug 11, 2021 · Updated Sep 17, 2024
Prototype pollution in merge-change before 3.0.0 allows attackers to modify Object.prototype through crafted property paths. The utils.set function splits a supplied path, recursively follows obj[currentPath], and assigns the final segment without rejecting proto, constructor, or prototype. Exploitation requires a consuming application to pass an attacker-controlled path; injected properties then affect objects sharing the prototype, while the ultimate consequence depends on application code that uses them.
Summary
What happened
Prototype pollution in merge-change before 3.0.0 allows attackers to modify Object.prototype through crafted property paths. The utils.set function splits a supplied path, recursively follows obj[currentPath], and assigns the final segment without rejecting proto, constructor, or prototype. Exploitation requires a consuming application to pass an attacker-controlled path; injected properties then affect objects sharing the prototype, while the ultimate consequence depends on application code that uses them.
The record
- CVE
- CVE-2021-23421
- Published
- Aug 11, 2021
- Updated
- Sep 17, 2024
- Vendor
- Vladimir Shestakov
- Product
- merge-change
- Classifications
- CWE-1321, CWE-915
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 11, 2021CVE publishedPublication date reported by the CVE source.
- Sep 17, 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?
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- Affected versionversion=0 <unspecified
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 prototype-pollution exploitation explanationproof of concept · unverified
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Technologies
Your stack
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Your stack
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