CVE-2026-50552

Koel is a free, open-source music streaming solution. Prior to version 9.7.1, Koel contains a Server-Side Request Forgery (SSRF) vulnerability in the radio station creation endpoint (POST /api/radio/stations). The url field validation rules are declared without the bail keyword, so the HasAudioContentType rule — which issues HTTP requests to the supplied URL — still executes even after the SafeUrl rule has rejected the URL as pointing to a private/reserved address. Any authenticated, non-admin user can therefore coerce the server into making HEAD/GET requests to arbitrary internal hosts. This issue has been patched in version 9.7.1.

Koel is a free, open-source music streaming solution. Prior to version 9.7.1, Koel contains a Server-Side Request Forgery (SSRF) vulnerability in the radio station creation endpoint (POST /api/radio/stations). The url field validation rules are declared without the bail keyword, so the HasAudioContentType rule — which issues HTTP requests to the supplied URL — still executes even after the SafeUrl rule has rejected the URL as pointing to a private/reserved address. Any authenticated, non-admin user can therefore coerce the server into making HEAD/GET requests to arbitrary internal hosts. This issue has been patched in version 9.7.1.

Summary

Koel v9.5.0 contains a Server-Side Request Forgery (SSRF) vulnerability in the radio station creation endpoint (POST /api/radio/stations). The url field validation rules are declared without the bail keyword, so the HasAudioContentType rule — which issues HTTP requests to the supplied URL — still executes even after the SafeUrl rule has rejected the URL as pointing to a private/reserved address. Any authenticated, non-admin user can therefore coerce the server into making HEAD/GET requests to arbitrary internal hosts.

This is a blind SSRF: the response body is never returned to the client, but the two distinct validation error messages form a reliable internal-network reachability oracle.

Severity

Medium — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N (5.4)

Authenticated (low-privilege) actor; blind SSRF (no response-body exfiltration). Confidentiality (L) reflects the internal reachability oracle; Integrity (L) reflects state-changing internal endpoints that act on GET/HEAD.

Affected Component

• Version: Koel v9.5.0 (latest release, HEAD b2e9a34, verified 2026-05-30)
• Endpoint: POST /api/radio/stations
• Files:
  • app/Http/Requests/API/Radio/RadioStationStoreRequest.php (missing bail)
  • app/Rules/HasAudioContentType.php (unguarded HTTP fetch)

Root Cause

app/Http/Requests/API/Radio/RadioStationStoreRequest.php (lines 25-34):

'url' => [
    'required',
    'url',
    Rule::unique('radio_stations')->where(function ($query) {
        return $query->where('user_id', $this->user()->id);
    }),
    new SafeUrl(),
    new HasAudioContentType(),
],

In Laravel, validation rules within a single attribute run in sequence and do not stop on the first failure unless bail is present or FormRequest::$stopOnFirstFailure is set. Neither is the case here (App\Http\Requests\Request does not override stopOnFirstFailure, and authorize() simply returns true).

For a directly-supplied private/reserved address (e.g. http://169.254.169.254, http://127.0.0.1:6379, http://192.168.0.1):

1. SafeUrl (app/Rules/SafeUrl.php lines 45-49) calls isPublicHost($uri->host()), fails it, calls $fail(...) and returns. SafeUrl itself does not make a request in this path — good.

2. Because there is no bail, validation continues to HasAudioContentType.

3. HasAudioContentType::resolveContentType() (app/Rules/HasAudioContentType.php lines 41-57) issues the request with no IP/host validation of its own:

   private function resolveContentType(string $url): string { try { $response = Http::head($url); // <-- SSRF if ($response->successful()) { return $response->header('Content-Type'); } } catch (Throwable) { }

    // Falls back to a streaming GET
    $response = Http::withHeaders(['Icy-MetaData' => '1'])
        ->withOptions(['stream' => true])
        ->get($url);                               // <-- SSRF
    return $response->header('Content-Type');
   

   }

The rule's own docblock (line 13-14) states "Should be used after SafeUrl to ensure the URL is safe to reach." — that assumption is silently violated by the missing bail.

Authorization Context

The endpoint is reachable by any authenticated user, not just admins:

• routes/api.base.php line 108 wraps the route group in Route::middleware('auth') only.
• routes/api.base.php line 268: Route::apiResource('stations', RadioStationController::class).
• RadioStationController::store() (lines 31-37) carries only #[DisabledInDemo] — no $this->authorize(...), no #[RequiresPlus], no permission check.

Reachability Oracle (Information Disclosure)

HasAudioContentType::validate() returns two distinct messages:

• Host unreachable / request throws → "The url couldn't be reached." (line 26)
• Host reachable but Content-Type is not audio/* → "The url doesn't look like a valid radio station URL." (line 32)

By diffing these responses an attacker can…

Koel is a free, open-source music streaming solution. Prior to version 9.7.1, Koel contains a Server-Side Request Forgery (SSRF) vulnerability in the radio station creation endpoint (POST /api/radio/stations). The url field validation rules are declared without the bail keyword, so the HasAudioContentType rule — which issues HTTP requests to the supplied URL — still executes even after the SafeUrl rule has rejected the URL as pointing to a private/reserved address. Any authenticated, non-admin user can therefore coerce the server into making HEAD/GET requests to arbitrary internal hosts. This issue has been patched in version 9.7.1.

Koel is a free, open-source music streaming solution. Prior to version 9.7.1, Koel contains a Server-Side Request Forgery (SSRF) vulnerability in the radio station creation endpoint (POST /api/radio/stations). The url field validation rules are declared without the bail keyword, so the HasAudioContentType rule — which issues HTTP requests to the supplied URL — still executes even after the SafeUrl rule has rejected the URL as pointing to a private/reserved address. Any authenticated, non-admin user can therefore coerce the server into making HEAD/GET requests to arbitrary internal hosts. This issue has been patched in version 9.7.1.

Summary

Koel v9.5.0 contains a Server-Side Request Forgery (SSRF) vulnerability in the radio station creation endpoint (POST /api/radio/stations). The url field validation rules are declared without the bail keyword, so the HasAudioContentType rule — which issues HTTP requests to the supplied URL — still executes even after the SafeUrl rule has rejected the URL as pointing to a private/reserved address. Any authenticated, non-admin user can therefore coerce the server into making HEAD/GET requests to arbitrary internal hosts.

This is a blind SSRF: the response body is never returned to the client, but the two distinct validation error messages form a reliable internal-network reachability oracle.

Severity

Medium — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N (5.4)

Authenticated (low-privilege) actor; blind SSRF (no response-body exfiltration). Confidentiality (L) reflects the internal reachability oracle; Integrity (L) reflects state-changing internal endpoints that act on GET/HEAD.

Affected Component

• Version: Koel v9.5.0 (latest release, HEAD b2e9a34, verified 2026-05-30)
• Endpoint: POST /api/radio/stations
• Files:
  • app/Http/Requests/API/Radio/RadioStationStoreRequest.php (missing bail)
  • app/Rules/HasAudioContentType.php (unguarded HTTP fetch)

Root Cause

app/Http/Requests/API/Radio/RadioStationStoreRequest.php (lines 25-34):

'url' => [
    'required',
    'url',
    Rule::unique('radio_stations')->where(function ($query) {
        return $query->where('user_id', $this->user()->id);
    }),
    new SafeUrl(),
    new HasAudioContentType(),
],

In Laravel, validation rules within a single attribute run in sequence and do not stop on the first failure unless bail is present or FormRequest::$stopOnFirstFailure is set. Neither is the case here (App\Http\Requests\Request does not override stopOnFirstFailure, and authorize() simply returns true).

For a directly-supplied private/reserved address (e.g. http://169.254.169.254, http://127.0.0.1:6379, http://192.168.0.1):

1. SafeUrl (app/Rules/SafeUrl.php lines 45-49) calls isPublicHost($uri->host()), fails it, calls $fail(...) and returns. SafeUrl itself does not make a request in this path — good.

2. Because there is no bail, validation continues to HasAudioContentType.

3. HasAudioContentType::resolveContentType() (app/Rules/HasAudioContentType.php lines 41-57) issues the request with no IP/host validation of its own:

   private function resolveContentType(string $url): string { try { $response = Http::head($url); // <-- SSRF if ($response->successful()) { return $response->header('Content-Type'); } } catch (Throwable) { }

    // Falls back to a streaming GET
    $response = Http::withHeaders(['Icy-MetaData' => '1'])
        ->withOptions(['stream' => true])
        ->get($url);                               // <-- SSRF
    return $response->header('Content-Type');
   

   }

The rule's own docblock (line 13-14) states "Should be used after SafeUrl to ensure the URL is safe to reach." — that assumption is silently violated by the missing bail.

Authorization Context

The endpoint is reachable by any authenticated user, not just admins:

• routes/api.base.php line 108 wraps the route group in Route::middleware('auth') only.
• routes/api.base.php line 268: Route::apiResource('stations', RadioStationController::class).
• RadioStationController::store() (lines 31-37) carries only #[DisabledInDemo] — no $this->authorize(...), no #[RequiresPlus], no permission check.

Reachability Oracle (Information Disclosure)

HasAudioContentType::validate() returns two distinct messages:

• Host unreachable / request throws → "The url couldn't be reached." (line 26)
• Host reachable but Content-Type is not audio/* → "The url doesn't look like a valid radio station URL." (line 32)

By diffing these responses an attacker can…