FKIE_CVE-2026-27707

Vulnerability from fkie_nvd - Published: 2026-02-27 20:21 - Updated: 2026-03-04 16:54
Summary
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.
Impacted products
Vendor Product Version
seerr seerr *

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:seerr:seerr:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "142465B9-9DE4-46F9-B457-572048968C86",
              "versionEndExcluding": "3.1.0",
              "versionStartIncluding": "2.0.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    },
    {
      "lang": "es",
      "value": "Seerr es un gestor de solicitudes y descubrimiento de medios de c\u00f3digo abierto para Jellyfin, Plex y Emby. A partir de la versi\u00f3n 2.0.0 y antes de la versi\u00f3n 3.1.0, una falla l\u00f3gica en la protecci\u00f3n de autenticaci\u00f3n en \u0027POST /API/v1/auth/jellyfin\u0027 permite a un atacante no autenticado registrar una nueva cuenta de Seerr en cualquier instancia configurada con Plex autentic\u00e1ndose con un servidor Jellyfin controlado por el atacante. El atacante recibe una sesi\u00f3n autenticada y puede usar inmediatamente la aplicaci\u00f3n con permisos predeterminados, incluida la capacidad de enviar solicitudes de medios a Radarr/Sonarr. Cualquier implementaci\u00f3n de Seerr donde se cumplan las tres condiciones siguientes puede ser vulnerable: \u0027settings.main.mediaServerType\u0027 est\u00e1 configurado como \u0027PLEX\u0027 (la implementaci\u00f3n m\u00e1s com\u00fan).; \u0027settings.jellyfin.ip\u0027 est\u00e1 configurado como \u0027\"\"\u0027 (predeterminado, lo que significa que Jellyfin nunca fue configurado); y \u0027settings.main.newPlexLogin\u0027 est\u00e1 configurado como \u0027true\u0027 (predeterminado). Las implementaciones configuradas con Jellyfin y Emby no se ven afectadas. La versi\u00f3n 3.1.0 de Seerr soluciona este problema."
    }
  ],
  "id": "CVE-2026-27707",
  "lastModified": "2026-03-04T16:54:47.437",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "LOW",
          "baseScore": 7.3,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.4,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      },
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2026-02-27T20:21:38.760",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/seerr-team/seerr/commit/4ae20684092b5b28527b23dfbc1a3417858fee8e"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Release Notes"
      ],
      "url": "https://github.com/seerr-team/seerr/releases/tag/v3.1.0"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Vendor Advisory",
        "Exploit"
      ],
      "url": "https://github.com/seerr-team/seerr/security/advisories/GHSA-rc4w-7m3r-c2f7"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-288"
        },
        {
          "lang": "en",
          "value": "CWE-807"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}


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