Object prototype modification via unsafe deepMerge recursion
Published Dec 10, 2021 · Updated Sep 17, 2024
Prototype pollution in C2FO comb 2.0.0 and earlier allows remote attackers to modify inherited object properties through deepMerge(). The function recursively enumerates attacker-controlled keys and follows target[name] without rejecting proto, causing assignments to reach Object.prototype. Exploitation requires an application to pass attacker-controlled objects to deepMerge; polluted properties can alter application logic or interrupt service.
Summary
What happened
Prototype pollution in C2FO comb 2.0.0 and earlier allows remote attackers to modify inherited object properties through deepMerge(). The function recursively enumerates attacker-controlled keys and follows target[name] without rejecting proto, causing assignments to reach Object.prototype. Exploitation requires an application to pass attacker-controlled objects to deepMerge; polluted properties can alter application logic or interrupt service.
The record
- CVE
- CVE-2021-23561
- Published
- Dec 10, 2021
- Updated
- Sep 17, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-1321
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 10, 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?
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
- Snyk deepMerge prototype-pollution proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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