CVE-2026-61826

CRITICAL CVSS 10.0 PoC Available

Published: 2026-10-30

Modified: 2026-10-30

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AI Threat Summary

CVE-2026-61826 is a critical vulnerability with a CVSS score of 10.0 affecting the target software. Threat hunters should monitor for exploit attempts and apply vendor patches immediately.

Description

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.

Attack Chain

Reconnaissance

Attacker identifies vulnerable service instances using Shodan, Censys, or active scanning

Initial Access

Attacker crafts malicious payload exploiting CVE-2026-61826 to achieve remote code execution

Execution

Attacker executes arbitrary OS commands or shellcode in the context of the vulnerable process

Persistence

Attacker installs backdoor, cron job, or web shell for persistent access

Lateral Movement

Attacker uses compromised host as pivot point to access internal network resources

MITRE ATT&CK Techniques

T1190 Exploit Public-Facing Application

Initial Access

Attacker exploits the vulnerability in an internet-facing service to gain initial access

T1059 Command and Scripting Interpreter

Execution

Post-exploitation shell commands executed through the vulnerability

T1105 Ingress Tool Transfer

Command and Control

Attacker downloads malware or tools after gaining code execution

Indicators of Compromise

Type	Value	Description
user_agent	`Mozilla/5.0 (compatible; exploit/1.0)`	Generic exploit scanner user agent pattern
url	`/api/vuln-endpoint?payload=<malicious>`	Exploit attempt against application endpoint — monitor access logs for anomalous params
registry_key	`HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\backdoor`	Persistence mechanism after successful RCE

Remediation

1. Apply vendor-supplied security patches immediately. 2. If patches are unavailable, apply recommended mitigations from the vendor advisory. 3. Enable WAF rules or IDS signatures to detect exploitation attempts. 4. Monitor logs for indicators of compromise listed above. 5. Implement network segmentation to limit blast radius if exploitation occurs. 6. Subscribe to vendor security advisories for this product.

Quick Facts

CVE ID	CVE-2026-61826
CVSS Score	10.0
Vector	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`
Published	2026-10-30
Exploited	No
CISA KEV	No
PoC	Available

References

External Resources

NVD Entry BleepingComputer The Hacker News