CVE-2026-21885: Miniflux Media Proxy SSRF via /proxy endpoint allows access to internal network resources

January 7, 2026 (updated January 8, 2026)

Miniflux’s media proxy endpoint (GET /proxy/{encodedDigest}/{encodedURL}) can be abused to perform Server-Side Request Forgery (SSRF). An authenticated user can cause Miniflux to generate a signed proxy URL for attacker-chosen media URLs embedded in feed entry content, including internal addresses (e.g., localhost, private RFC1918 ranges, or link-local metadata endpoints). Requesting the resulting /proxy/... URL makes Miniflux fetch and return the internal response.

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Code Behaviors & Features

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