Object prototype modification via hijacked Array.includes
Published Feb 11, 2026 · Updated Feb 11, 2026
Prototype pollution in ahdinosaur set-in 2.0.1 through 2.0.4 allows local users to modify Object.prototype via a crafted key path. The recursivelySetIn path filter calls Array.prototype.includes on a forbidden-key list, so replacing includes with a false-returning function lets constructor and prototype segments pass. Exploitation requires control of Array.prototype in the same JavaScript runtime and a downstream call using the crafted path; consequences depend on how the application later uses polluted properties.
Summary
What happened
Prototype pollution in ahdinosaur set-in 2.0.1 through 2.0.4 allows local users to modify Object.prototype via a crafted key path. The recursivelySetIn path filter calls Array.prototype.includes on a forbidden-key list, so replacing includes with a false-returning function lets constructor and prototype segments pass. Exploitation requires control of Array.prototype in the same JavaScript runtime and a downstream call using the crafted path; consequences depend on how the application later uses polluted properties.
The record
- CVE
- CVE-2026-26021
- Published
- Feb 11, 2026
- Updated
- Feb 11, 2026
- Vendor
- ahdinosaur
- Product
- set-in
- Classifications
- CWE-1321
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 11, 2026CVE publishedPublication date reported by the CVE source.
- Feb 11, 2026Record 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, < 2.0.5
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
- Maintainer advisory Array.prototype.includes bypass proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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