Object prototype modification via unsafe nested parsing
Published Apr 23, 2021 · Updated Nov 3, 2025
Prototype pollution in Ben Alman jQuery BBQ 1.2.1 allows attackers to modify Object.prototype through a crafted query string. The jq_deparam function splits bracketed parameter names and walks inherited constructor and prototype properties without blocking them, then assigns the supplied value to Object.prototype. Exploitation requires an application to pass attacker-controlled URL data to $.deparam; resulting effects depend on the application's use of polluted properties.
Summary
What happened
Prototype pollution in Ben Alman jQuery BBQ 1.2.1 allows attackers to modify Object.prototype through a crafted query string. The jq_deparam function splits bracketed parameter names and walks inherited constructor and prototype properties without blocking them, then assigns the supplied value to Object.prototype. Exploitation requires an application to pass attacker-controlled URL data to $.deparam; resulting effects depend on the application's use of polluted properties.
The record
- CVE
- CVE-2021-20086
- Published
- Apr 23, 2021
- Updated
- Nov 3, 2025
- Vendor
- Ben Alman
- Product
- jQuery BBQ
- Classifications
- CWE-1321
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 23, 2021CVE publishedPublication date reported by the CVE source.
- Nov 3, 2025Record 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=1.2.1
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
- jQuery BBQ client-side 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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