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Emby.releasesApplication · Emby

CVE-2021-32833

HIGH · 8.6 CVSS v3.1 Published 2021-09-09
Fix available
A fix is available. Upgrade to after 4.6.4.0 or later.
See remediation →
95/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Emby Server is a personal media server with apps on many devices. In Emby Server on Windows there is a set of arbitrary file read vulnerabilities. This vulnerability is known to exist in version 4.6.4.0 and may not be patched in later versions. Known vulnerable routes are /Videos/Id/hls/PlaylistId/SegmentId.SegmentContainer, /Images/Ratings/theme/name and /Images/MediaInfo/theme/name. For more details including proof of concept code, refer to the referenced GHSL-2021-051. This issue may lead to unauthorized access to the system especially when Emby Server is configured to be accessible from the Internet.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis

A detailed technical summary for this CVE is being prepared.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Emby.releasesApplication
Affected:<= 4.6.4.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 4.6.4.0
Recommended fix Low confidence
  1. Check the Emby Server release notes and security advisories for any security updates beyond version 4.6.4.0
  2. If no security patch is available, consider network-level mitigation: restrict access to Emby Server to trusted networks only via firewall rules or VPN
  3. If exposed to the internet, implement strong authentication and consider using a reverse proxy with authentication (e.g., Nginx with basic auth, or OAuth)
  4. Review Emby Server configuration and ensure remote access features are disabled if not needed
  5. Monitor Emby official forums and GitHub repositories for security updates addressing CVE-2021-32833
  6. Consider alternative media server solutions if no patch becomes available

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-32833 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data