vulnerability / NVI-00007442 / Revision 2
Koel has SSRF through Authenticated Subsonic podcast feed URLs
GitHub lists this reviewed advisory for phanan/koel. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
6.4 medium
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
phanan/koel
source listed<= 9.6.0
## Summary Koel's Subsonic `createPodcastChannel.view` endpoint accepts a user supplied podcast feed URL and fetches it server-side before applying the safe URL checks that are used for podcast episode enclosure URLs. An authenticated Subsonic API user can provide a loopback or internal URL as the feed URL and cause the Koel backend to issue a request to that address. A related redirect gap exists in the podcast stream helper: `PodcastService::getStreamableUrl()` validates only the original URL, then lets Guzzle follow redirects and accepts the final redirected URL without re-validating it. ## Impact An attacker with any valid Koel account and Subsonic API key can trigger server-side requests from the Koel host to loopback or internal network services. This can be used for blind SSRF against internal HTTP endpoints reachable by the Koel deployment. If an internal service returns valid RSS/XML or permissive CORS responses, parts of the response or final URL may be reflected back through normal podcast or stream behavior. ## Reproduction 1. Start Koel v9.6.0 or current main and create a normal user. 2. Obtain the user's Subsonic API key. 3. Start a local canary HTTP server on t
phanan/koel
source listedECOSYSTEM: introduced 0; fixed 9.7.0
## Summary Koel's Subsonic `createPodcastChannel.view` endpoint accepts a user supplied podcast feed URL and fetches it server-side before applying the safe URL checks that are used for podcast episode enclosure URLs. An authenticated Subsonic API user can provide a loopback or internal URL as the feed URL and cause the Koel backend to issue a request to that address. A related redirect gap exists in the podcast stream helper: `PodcastService::getStreamableUrl()` validates only the original URL, then lets Guzzle follow redirects and accepts the final redirected URL without re-validating it. ## Impact An attacker with any valid Koel account and Subsonic API key can trigger server-side requests from the Koel host to loopback or internal network services. This can be used for blind SSRF against internal HTTP endpoints reachable by the Koel deployment. If an internal service returns valid RSS/XML or permissive CORS responses, parts of the response or final URL may be reflected back through normal podcast or stream behavior. ## Reproduction 1. Start Koel v9.6.0 or current main and create a normal user. 2. Obtain the user's Subsonic API key. 3. Start a local canary HTTP server on t
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
- vendor patch
The original advisory lists fixed boundaries 9.7.0 for phanan/koel. Confirm the publisher’s latest guidance.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database via OSV
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-8q6q-m837-fv64 ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- GHSA-8q6q-m837-fv64 ↗
GitHub Advisory Database via OSV · vendor advisory
Observed . GitHub-origin advisory, CC-BY-4.0; OSV is an aggregate copy, not independent corroboration.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 2 ·
Source facts changed; compare the preserved prior revision.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.