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.
Advisories

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Fixes

Solution

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Workaround

No workaround given by the vendor.

History

Wed, 04 Mar 2026 17:00:00 +0000

Type Values Removed Values Added
First Time appeared Seerr
Seerr seerr
CPEs cpe:2.3:a:seerr:seerr:*:*:*:*:*:*:*:*
Vendors & Products Seerr
Seerr seerr

Mon, 02 Mar 2026 12:15:00 +0000

Type Values Removed Values Added
First Time appeared Seerr-team
Seerr-team seerr
Vendors & Products Seerr-team
Seerr-team seerr

Fri, 27 Feb 2026 21:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 27 Feb 2026 19:45:00 +0000

Type Values Removed Values Added
Description 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.
Title Plex-configured Seerr instances vulnerable to unauthenticated account registration via Jellyfin authentication endpoint
Weaknesses CWE-288
CWE-807
References
Metrics cvssV3_1

{'score': 7.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-02-27T20:22:24.091Z

Reserved: 2026-02-23T17:56:51.203Z

Link: CVE-2026-27707

cve-icon Vulnrichment

Updated: 2026-02-27T20:22:18.084Z

cve-icon NVD

Status : Analyzed

Published: 2026-02-27T20:21:38.760

Modified: 2026-03-04T16:54:47.437

Link: CVE-2026-27707

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-03-02T12:05:10Z

Weaknesses