Authenticated JavaScript execution via unvalidated postMessage origin
Published Dec 19, 2025 · Updated Dec 19, 2025
Stored XSS in Foxit PDF Editor Cloud plugin service before 2025-12-01 allows remote authenticated users to execute JavaScript. Its postMessage handler accepts messages without checking their origin and assigns attacker-controlled externalPath directly to a script element's source. Exploitation requires low-privileged access and user interaction, and successful execution runs attacker-supplied JavaScript in the affected web context.
Summary
What happened
Stored XSS in Foxit PDF Editor Cloud plugin service before 2025-12-01 allows remote authenticated users to execute JavaScript. Its postMessage handler accepts messages without checking their origin and assigns attacker-controlled externalPath directly to a script element's source. Exploitation requires low-privileged access and user interaction, and successful execution runs attacker-supplied JavaScript in the affected web context.
The record
- CVE
- CVE-2025-66500
- Published
- Dec 19, 2025
- Updated
- Dec 19, 2025
- Vendor
- Foxit Software
- Product
- Foxit PDF Editor Cloud plugin service
- Classifications
- CWE-79, T1203
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Dec 19, 2025CVE publishedPublication date reported by the CVE source.
- Dec 19, 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=before 2025‑12‑01
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
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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