CVE-2026-33126: 
NixOS vulnerability analysis and mitigation

CVE-2026-33126 is a Server-Side Request Forgery (SSRF) vulnerability in Frigate, an open-source network video recorder (NVR) with real-time local object detection for IP cameras. The vulnerability exists in the /ffprobe endpoint, which accepts arbitrary user-controlled URLs without proper validation. All Frigate versions prior to 0.16.3 are affected. It was published on March 20, 2026, and patched in version 0.16.3. The CVSS v3.1 base score is 5.0 (Moderate) per the GitHub Security Advisory, with NVD scoring it at 4.3 (Medium) (GitHub Advisory, Red Hat CVE).

The root cause is improper input validation (CWE-918: Server-Side Request Forgery) in the /ffprobe API endpoint located in /frigate/api/camera.py. The endpoint https://<host>/api/ffprobe?paths=<URL> accepts any URL supplied by the user without restricting it to legitimate camera stream protocols, enabling the Frigate server to be used as a proxy to make outbound HTTP requests to arbitrary destinations. Exploitation requires only low-privilege authenticated access (Viewer role), with no user interaction needed. A public proof-of-concept demonstrating the attack using a Burp Collaborator URL is included in the security advisory (GitHub Advisory).

Successful exploitation allows an authenticated attacker to leverage the Frigate server as an HTTP proxy to reach internal network resources, cloud instance metadata services (e.g., AWS IMDSv1 at 169.254.169.254), and services protected by firewalls. This enables information disclosure (determining the existence of internal hosts and services), firewall bypass (accessing internal services not exposed to the internet), and port scanning of the internal network. While confidentiality and availability impacts are rated as none in the CVSS scoring, the integrity and reconnaissance potential poses meaningful risk in environments where Frigate is deployed alongside sensitive internal infrastructure (GitHub Advisory).

A proof-of-concept exploit is publicly available in the GitHub Security Advisory, demonstrating the specific endpoint, parameter, and payload structure required to trigger the SSRF. Exploitation requires only low-privilege authenticated access (Viewer role), making it accessible to a broad range of potential attackers. There is no evidence of active in-the-wild exploitation at this time, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. The EPSS score is approximately 0.026%, reflecting low current exploitation probability (GitHub Advisory).

1. Obtain low-privilege access: Acquire Viewer-level credentials to a Frigate instance running a version prior to 0.16.3. This may be achieved through credential theft, default credentials, or social engineering.
2. Identify the target Frigate instance: Locate an internet-facing or network-accessible Frigate server. Shodan or Censys can be used to identify exposed instances.
3. Set up an out-of-band callback server: Configure a Burp Collaborator instance or similar SSRF detection server (e.g., interactsh) to capture incoming HTTP requests.
4. Send the SSRF payload: Issue an authenticated HTTP GET request to the vulnerable endpoint with an attacker-controlled URL as the paths parameter:

   GET /api/ffprobe?paths=https://<attacker-collaborator-host> HTTP/1.1
   Host: <frigate-host>
   Authorization: <viewer-session-token>

5. Confirm SSRF: Observe the incoming request on the callback server, confirming the Frigate server is making outbound HTTP requests on behalf of the attacker.
6. Pivot to internal resources: Replace the callback URL with internal targets such as http://169.254.169.254/latest/meta-data/ (cloud metadata), internal API endpoints, or private IP ranges to enumerate services and extract information (GitHub Advisory).

• Network: Outbound HTTP requests from the Frigate server to unexpected external hosts, cloud metadata endpoints (e.g., 169.254.169.254), or internal IP ranges not associated with configured cameras; DNS lookups for attacker-controlled domains originating from the Frigate host.
• Logs: Frigate API access logs showing repeated GET requests to /api/ffprobe with paths parameter values containing non-camera URLs (e.g., http://, https:// pointing to external or internal hosts); unusual response times or errors from the ffprobe endpoint.
• Process: The Frigate process initiating network connections to IP addresses or hostnames not corresponding to any configured camera streams.

The primary remediation is to upgrade Frigate to version 0.16.3 or later (also fixed in 0.17.0-beta1 and above), which addresses this SSRF vulnerability (Frigate Release). For deployments that cannot immediately upgrade, apply the following mitigations: restrict the /ffprobe endpoint to admin-only access by adding dependencies=[Depends(require_role(["admin"]))]; implement strict URL validation on the paths parameter to allow only legitimate camera stream protocols (e.g., rtsp://, rtmp://); and apply network egress controls to limit the Frigate server's outbound HTTP connectivity to only necessary resources, blocking access to internal RFC 1918 address ranges and cloud metadata services (GitHub Advisory).

The vulnerability was reported by security researcher czerlun and disclosed via GitHub's coordinated vulnerability disclosure process. The Frigate maintainers addressed the issue promptly in the v0.16.3 release. No significant broader media coverage or notable public researcher commentary beyond the advisory itself has been identified at this time (GitHub Advisory, Frigate Release).