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CVE-2026-27707— Plex-configured Seerr instances vulnerable to unauthenticated account registration via Jellyfin authentication endpoint

Quick assessment

Affected
seerr-team seerr
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

seerr是Seerr Team开源的一个媒体请求和发现管理器。 seerr 2.0.0至3.1.0之前版本存在安全漏洞，该漏洞源于身份验证防护逻辑缺陷，可能导致未经身份验证的攻击者注册新账户并获得默认权限。

CVSS 7.3 · High EPSS 0.69% · P51
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I. Basic Information for CVE-2026-27707

Vulnerability Information
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Vulnerability Title
Plex-configured Seerr instances vulnerable to unauthenticated account registration via Jellyfin authentication endpoint
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
使用候选路径或通道进行的认证绕过
Source: CVE Program / CVE List V5
Vulnerability Title
seerr 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
seerr是Seerr Team开源的一个媒体请求和发现管理器。 seerr 2.0.0至3.1.0之前版本存在安全漏洞，该漏洞源于身份验证防护逻辑缺陷，可能导致未经身份验证的攻击者注册新账户并获得默认权限。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
seerr-team seerr >= 2.0.0, < 3.1.0 -

II. Public POCs for CVE-2026-27707

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III. Intelligence Information for CVE-2026-27707

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Patches & Fixes for CVE-2026-27707 (1)

Vendor Advisories for CVE-2026-27707 (1)

Same Patch Batch · seerr-team · 2026-02-27 · 3 CVEs total

CVE-2026-27793 6.5 MEDIUM Seerr has Broken Object-Level Authorization in User Profile Endpoint that Exposes Third-Pa
CVE-2026-27792 5.4 MEDIUM Seerr missing authentication on pushSubscription endpoints

IV. Related Vulnerabilities

Same product: seerr
Same vendor: seerr-team
Same weakness: CWE-288

V. Comments for CVE-2026-27707

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