Omnivore EUVD-2026-63255

A valid authenticated Omnivore session is required (CVSS PR:L confirmed) - unauthenticated actors cannot reach the scanFeedsResolver endpoint. The attacker must be able to submit a scanFeeds GraphQL mutation to the Omnivore API. No special server configuration is needed; the vulnerability exists in the default deployment of the API package. Exploitation is limited by the response parser: only feed-shaped metadata fields (url, title, description, type) and advertised RSS/Atom link elements from the fetched response are returned - raw HTTP response bodies are not exposed. However, port reachability can still be inferred through error differentiation even when content is not parseable as a feed. The Omnivore server must have outbound network access to the targeted internal addresses for exploitation to succeed; network egress filtering to RFC-1918 and link-local ranges blocks the attack independently of the application-layer fix.

The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N) yields a score of 5.3, placing this in the medium band. The PR:L metric is the primary mitigating factor: exploitation is gated behind a valid authenticated session, excluding unauthenticated actors. Impact is intentionally bounded by the response parser - only feed-shaped metadata and link elements are surfaced, not raw HTTP response bodies - which distinguishes this from full-response SSRF variants that can exfiltrate arbitrary secrets. The SC:L rating reflects that subsequent internal systems can have their metadata partially exposed. No EPSS data was provided, the vulnerability is not listed in CISA KEV, and no public exploit code has been identified, all of which suggest this has not been broadly weaponized. Practical risk scales with deployment context: an Omnivore instance whose API server has outbound access to cloud metadata services (e.g., AWS IMDSv1 at 169.254.169.254) or internal APIs faces meaningful lateral-movement exposure even with limited response fidelity, because port reachability inference alone can map internal topology. Organizations without network-level egress controls between the Omnivore server and sensitive internal resources should treat the patch as a priority.

An authenticated Omnivore user submits a scanFeeds GraphQL mutation supplying an internal URL such as http://169.254.169.254/latest/meta-data/ (AWS IMDSv1) as the target. The server fetches the URL via axios; if the response contains parseable feed metadata or HTML link elements advertising RSS/Atom feeds, those fields are returned to the attacker. Even when the target does not return parseable feed content, the attacker can distinguish open from closed internal ports through differing error responses, enabling systematic internal network enumeration from an authenticated session.