Administrator-context script execution via stored client-name XSS
Published Nov 18, 2025 · Updated Nov 19, 2025
Stored XSS in Emby Server before 4.8.1.0 and Beta before 4.9.0.0-beta allows remote authenticated users to run administrator-context script. The authentication endpoint stores the unescaped X-Emby-Client header as a device name, and the admin dashboard renders it as active markup. A valid user account and an administrator viewing the devices section are required; the injected script runs with the administrator's web-session access to service endpoints.
Summary
What happened
Stored XSS in Emby Server before 4.8.1.0 and Beta before 4.9.0.0-beta allows remote authenticated users to run administrator-context script. The authentication endpoint stores the unescaped X-Emby-Client header as a device name, and the admin dashboard renders it as active markup. A valid user account and an administrator viewing the devices section are required; the injected script runs with the administrator's web-session access to service endpoints.
The record
- CVE
- CVE-2025-64325
- Published
- Nov 18, 2025
- Updated
- Nov 19, 2025
- Vendor
- Media Browser
- Product
- Emby.Security
- Classifications
- CWE-79, CWE-116, T1203
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Nov 18, 2025CVE publishedPublication date reported by the CVE source.
- Nov 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=Emby Server Beta (Web App) < 4.9.0.0-beta
- Affected versionversion=Emby Server (Web App) < 4.8.1.0
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
- Vendor advisory X-Emby-Client stored-XSS requestproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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