CVE-2023-33193
Emby.Releases ≤ 4.7.0.12
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:NCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2023-33193 is a critical-severity HTTP Request/Response Smuggling (CWE-444) vulnerability in Emby Emby.Releases. Its CVSS base score is 9.1 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique LSASS Memory (T1003.001); ranked in the top 23% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
Emby Server, a user-installable home media server, contains a header spoofing vulnerability that affects the local versus non-local network determination logic used for reverse proxy interoperability. By manipulating specific headers, an unauthenticated remote attacker can bypass intended access controls on publicly reachable installations where administrative accounts lack password requirements or other hardening. The flaw is tracked as CWE-444 and carries a CVSS 3.1 score of 9.1.
An attacker with network access to an exposed Emby Server instance can spoof the relevant headers to either enumerate user accounts that have no password set or obtain administrative login without credentials, depending on the server's account configuration. This requires no prior authentication and succeeds against default or loosely configured deployments.
The official Emby security advisory states that the issue is resolved in Emby Server 4.7.12 and Beta 4.8.31; administrators are advised to apply these updates and restrict administrative accounts to require passwords. The associated EPSS score reached a peak of 0.5704 before receding to its current value of 0.4567.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-37370
Vulnerability Data
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…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V4.1.3V4.2.4V1.5.3V4.1.1
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Network monitoring can detect smuggling attempts via anomalous HTTP traffic or logs, while eliminating the inconsistency directly aids detection of such events.
Network protections can enforce consistent HTTP proxy/firewall behavior to block smuggling, and removing the weakness helps prevent unauthorized access via request smuggling.
Configuration management can enforce uniform HTTP parsing rules across intermediaries, directly mitigating inconsistent interpretation.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.