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Seerr CVE-2026-27707

HIGH
Authentication Bypass Using an Alternate Path or Channel (CWE-288)
2026-02-27 security-advisories@github.com
7.3
CVSS 3.1 · GitHub Advisory
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Severity by source

GitHub Advisory PRIMARY
7.3 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

Lifecycle Timeline

4
Analysis Generated
Mar 12, 2026 - 21:55 vuln.today
PoC Detected
Mar 04, 2026 - 16:54 vuln.today
Public exploit code
Patch released
Mar 04, 2026 - 16:54 nvd
Patch available
CVE Published
Feb 27, 2026 - 20:21 nvd
HIGH 7.3

DescriptionGitHub Advisory

Seerr is an open-source media request and discovery manager for Jellyfin, Plex, and Emby. Starting in version 2.0.0 and prior to version 3.1.0, an authentication guard logic flaw in POST /api/v1/auth/jellyfin allows an unauthenticated attacker to register a new Seerr account on any Plex-configured instance by authenticating with an attacker-controlled Jellyfin server. The attacker receives an authenticated session and can immediately use the application with default permissions, including the ability to submit media requests to Radarr/Sonarr. Any Seerr deployment where all three of the following are true may be vulnerable: settings.main.mediaServerType is set to PLEX (the most common deployment).; settings.jellyfin.ip is set to "" (default, meaning Jellyfin was never configured); and settings.main.newPlexLogin is set to true (default). Jellyfin-configured and Emby-configured deployments are not affected. Version 3.1.0 of Seerr fixes this issue.

AnalysisAI

Seerr is an open-source media request and discovery manager for Jellyfin, Plex, and Emby. [CVSS 7.3 HIGH]

Technical ContextAI

Affects Seerr. Seerr is an open-source media request and discovery manager for Jellyfin, Plex, and Emby. Starting in version 2.0.0 and prior to version 3.1.0, an authentication guard logic flaw in POST /api/v1/auth/jellyfin allows an unauthenticated attacker to register a new Seerr account on any Plex-configured instance by authenticating with an attacker-controlled Jellyfin server. The attacker receives an authenticated session and can immediately use the application with default permissions, including the

RemediationAI

A vendor patch is available — apply it immediately. Restrict network access to the affected service where possible.

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CVE-2026-27707 vulnerability details – vuln.today

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