CVE-2026-47260: Koel Vulnerable to SSRF via Podcast Episode Enclosure URLs

Synopsis

This is a server-side request forgery (SSRF) vulnerability in Koel, a self-hosted music streaming application. The flaw is reachable over the network by any authenticated user with a low-privilege account, because Koel validates the top-level podcast feed URL but skips validation on individual episode enclosure URLs extracted from RSS XML, storing them directly in the database. When a user triggers playback of a crafted episode, the Koel server fetches the full HTTP response from the attacker-controlled enclosure URL and streams it back, giving the attacker the ability to read responses from internal services that are not exposed to the public network. A fix was introduced in version 9.3.5; patched-image rebuilds at that version are available on HarborGuard for affected environments.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

  The attacker must reach the Koel service over the network; the CVSS vector specifies AV:N, meaning no local or physical access to the host is needed.

• AuthenticationRequired

  The attacker must hold a valid Koel account, though any low-privilege user account is sufficient; the CVSS vector specifies PR:L.

• Victim interactionNot required

  No other user needs to take any action; the attacker triggers the SSRF directly by initiating episode playback themselves.

• Attack complexityDetail

  The exploit is reliable and condition-free; the CVSS vector specifies AC:L, meaning no race conditions or special environmental factors are needed.

Blast Radius

• The attacker reads full HTTP responses from internal services reachable by the Koel server, such as metadata APIs, cloud instance metadata endpoints, or internal dashboards.
• Internal service responses are streamed back to the attacker through the legitimate episode playback channel, bypassing network perimeter controls that would otherwise block direct access.
• Confidentiality impact is rated High in the CVSS vector; there is no integrity or availability impact, so data modification and service disruption are not in scope for this vulnerability.