> CVE-2026-27707 [HIGH]

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PUBLISHED
2026-02-27 20:21
MODIFIED
2026-02-27 20:21
CVSS_SCORE V3
7.3
EPSS (Prob. Exploit)
0.70%
Top 47.2%
DATA SOURCES:
NVD đź”— 2026-02-27 CWE MITRE đź”— 2026-11-01 FIRST EPSS đź”— 2026-10-25 OSV đź”— 2026-03-06

> 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.

> AFFECTED_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> CVSS V3 METRICS

CVSS_VECTOR
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
EXPLOITABILITY
3.9
IMPACT
3.4

> MÉTRIQUES CVSS DÉTAILLÉES

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Métrique Valeur Interprétation
AV (Vecteur d'Attaque)
Attack Vector
Network (N)
Exploit possible à distance via réseau (HTTP, API, etc.)
AC (Complexité d'Attaque)
Attack Complexity
Low (L)
Peu de conditions requises pour exploiter
PR (Privilèges Requis)
Privileges Required
None (N)
Aucune authentification requise
UI (Interaction Utilisateur)
User Interaction
None (N)
Aucune interaction utilisateur nécessaire
S (Périmètre)
Scope
Unchanged (U)
Impact reste dans le périmètre du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
Low (L)
Divulgation limitée d'informations
I (Impact Intégrité)
Integrity Impact
Low (L)
Modification limitée des données possible
A (Impact Disponibilité)
Availability Impact
Low (L)
Interruption partielle du service possible

> RÉSUMÉ DES IMPACTS

Confidentialité
Low
Divulgation limitée d'informations
Intégrité
Low
Modification limitée des données possible
Disponibilité
Low
Interruption partielle du service possible

> WEAKNESSES

CWE-288 CWE-807

> CWE DETAILED DESCRIPTIONS

CWE-288: Authentication Bypass Using an Alternate Path or Channel - The product requires authentication, but the product has an alternate path or channel that does not require authentication. | CWE-807: Reliance on Untrusted Inputs in a Security Decision - The product uses a protection mechanism that relies on the existence or values of an input, but the input can be modified by an untrusted actor in a way that bypasses the protection mechanism.

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

Plex-configured Seerr instances vulnerable to unauthenticated account registration via Jellyfin authentication endpoint

AFFECTED PACKAGES:
Unknown / Unknown
19 versions affected
ALIASES:
GHSA-rc4w-7m3r-c2f7

> HISTORIQUE DES MODIFICATIONS

Première apparition
27/02/2026 20:21
Source: NVD
📊 ENRICHISSEMENT 01/03/2026 06:46
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-288: Authentication Bypass Using an Alternate Path or Channel - The product requires authentication, but the product has an alternate path or channel that does not require authentication. | CWE-80...
Total des modifications: 1 Dernière mise à jour: 8 months ago

> REFERENCES

https://github.com/seerr-team/seerr/commit/4ae20684092b5b28527b23dfbc1a3417858fe...
https://github.com/seerr-team/seerr/releases/tag/v3.1.0
https://github.com/seerr-team/seerr/security/advisories/GHSA-rc4w-7m3r-c2f7
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