CVE-2023-33193: Emby Server Proxy Header Spoofing Vulnerability

Severity: critical (CVSS 9.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.7% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2023-05-30 · updated 2026-06-17
Weakness: CWE-444

Description

Emby Server is a user-installable home media server which stores and organizes a user's media files of virtually any format and makes them available for viewing at home and abroad on a broad range of client devices. This vulnerability may allow administrative access to an Emby Server system, depending on certain user account settings. By spoofing certain headers which are intended for interoperation with reverse proxy servers, it may be possible to affect the local/non-local network determination to allow logging in without password or to view a list of user accounts which may have no password configured. Impacted are all Emby Server system which are publicly accessible and where the administrator hasn't tightened the account login configuration for administrative users. This issue has been patched in Emby Server Beta version 4.8.31 and Emby Server version 4.7.12.

Affected products

Media Browser Emby Server: before 4.7.0.12; from 4.8.0.0 before 4.8.31 — fixed in 4.7.0.12, 4.8.31

How to fix

Upgrade to a fixed version: Media Browser Emby Server 4.7.0.12, 4.8.31. Check the vendor advisory for mitigations.

References

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