Prototype pollution via recursive __proto__ copying
Published Jan 7, 2022 · Updated Sep 16, 2024
Prototype pollution in EggJS extend2 before 1.0.1 allows attackers to modify shared object properties through a crafted merge source. The extend function recursively copies enumerable keys and follows the special proto property into Object.prototype instead of rejecting it. Applications that pass attacker-controlled objects into a deep merge can inherit injected properties process-wide, enabling application-dependent data changes, crashes, or code execution.
Summary
What happened
Prototype pollution in EggJS extend2 before 1.0.1 allows attackers to modify shared object properties through a crafted merge source. The extend function recursively copies enumerable keys and follows the special proto property into Object.prototype instead of rejecting it. Applications that pass attacker-controlled objects into a deep merge can inherit injected properties process-wide, enabling application-dependent data changes, crashes, or code execution.
The record
- CVE
- CVE-2021-23568
- Published
- Jan 7, 2022
- Updated
- Sep 16, 2024
- Vendor
- EggJS
- Product
- extend2
- Classifications
- CWE-1321
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 7, 2022CVE 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=unspecified <1.0.1
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
- Snyk extend2 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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