JavaScript execution via inherited HTML attributes
Published Jul 25, 2025 · Updated Dec 3, 2025
Prototype pollution in Linkify 4.3.1 allows remote attackers to execute JavaScript through injected HTML event-handler attributes. The internal assign() helper copies enumerable properties without filtering proto, and inherited keys are later written to generated links with setAttribute(). Remote reachability requires a consuming application to pass attacker-controlled attributes into Linkify; successful exploitation yields stored or reflected XSS in rendered links.
Summary
What happened
Prototype pollution in Linkify 4.3.1 allows remote attackers to execute JavaScript through injected HTML event-handler attributes. The internal assign() helper copies enumerable properties without filtering proto, and inherited keys are later written to generated links with setAttribute(). Remote reachability requires a consuming application to pass attacker-controlled attributes into Linkify; successful exploitation yields stored or reflected XSS in rendered links.
The record
- CVE
- CVE-2025-8101
- Published
- Jul 25, 2025
- Updated
- Dec 3, 2025
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-1321, CAPEC-243, CAPEC-77, T1059.007
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 25, 2025CVE publishedPublication date reported by the CVE source.
- Dec 3, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
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
- poc-proto-xss.jsproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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