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Fencer Vulns
critical 10.0

CVE-2026-61826 json

Bazarr: Plex OAuth API namespace is entirely unauthenticated, allowing config tampering, integration takeover and server-side request forgery

published 2026-10-30 9 d ago modified 2026-11-05 4 d ago also EUVD-2026-114256

cvss
10.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 18%
public exploits
0
none known

Summary

Bazarr is a companion application to Sonarr and Radarr. Prior to 1.5.7-beta.14, the `api_ns_plex` namespace in `bazarr/api/plex/oauth.py` omits `@authenticate` on its Resource handlers, while normal APIs require an API key and no global authentication hook compensates. Anonymous callers can invoke `POST /api/plex/oauth/logout` to clear credentials and disable the integration, or `POST /api/plex/apikey` to persist an attacker-selected key, without a PIN, account or state precondition. `POST /api/plex/oauth/pin` and `GET /api/plex/oauth/pin/<pin_id>/check` additionally allow an attacker who completes a PIN with an attacker-controlled Plex account to bind that account's token to the instance. `PlexPinCheck` skips state validation when `state_param` is absent and merely logs a mismatch without stopping execution. `POST /api/plex/select-server`, `POST /api/plex/oauth/servers`, `POST /api/plex/webhook/create`, `POST /api/plex/webhook/delete` and `POST /api/plex/encrypt-apikey` expose further `write_config()` operations. Attacker-controlled server URLs feed later outbound requests carrying the configured API key in `X-Plex-Token`, enabling server-side request forgery and credential exposure in addition to persistent configuration tampering and integration denial of service. Version 1.5.7-beta.14 closes the anonymous API-mutation path by adding authentication; complete OAuth state validation is not established and remains a separate residual for curator review.

Patch / fix

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
4 d ago

Exploit prediction

0.26% chance of exploitation in the next 30 days, higher than 18% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Affected products

  • morpheus65535 bazarr

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.