Miniflux Media Proxy SSRF via /proxy endpoint allows access to internal network resources

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.5 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS

• CVE-2026-21885: 0.30% estimated exploitation activity in the next 30 days; percentile 22.80 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary 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. Details - Vulnerable route: GET /proxy/{encodedDigest}/{encodedURL} (accessible without authentication, but requires a server-generated HMAC-signed URL) - Handler: internal/ui/proxy.go ((handler).mediaProxy) - Trigger: entry content is rewritten to proxy media URLs (e.g., mediaproxy.RewriteDocumentWithAbsoluteProxyURL(...)), producing signed /proxy/... URLs. - Root cause: the proxy validates the URL scheme and HMAC signature, but does not restrict target hosts/IPs. As a result, requests to…

Published by the source

7 Jan 2026, 19:22 UTC

Last modified by the source

8 Jan 2026, 21:19 UTC

Source last checked

26 Oct 2026, 15:14 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-xwh2-742g-w3wp

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# Patch Next advisory brief: CVE-2026-21885

Advisory: Miniflux Media Proxy SSRF via /proxy endpoint allows access to internal network resources
IDs: CVE-2026-21885, GHSA-xwh2-742g-w3wp
Record: https://patchnext.com/advisories/cve-2026-21885 (revision 1, source checked 26 Oct 2026, 15:14 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: miniflux.app/v2 2.2.16. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go miniflux.app/v2: affected <= 2.2.15; fixed in 2.2.16

## Suggested inspection (read-only)
- Go miniflux.app/v2: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on miniflux.app/v2.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-xwh2-742g-w3wp (GitHub-reviewed advisory GHSA-xwh2-742g-w3wp lists affected ranges: Go miniflux.app/v2 >=0 <=2.2.15)

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