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GHSA-xwh2-742g-w3wp

MediumCVSS 6.5 / 10
Published Jan 7, 2026·Last modified Feb 3, 2026
Affected Components(0)

No affected components available

Description

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 loopback/private/link-local addresses are allowed and fetched by the server.

PoC

  1. Run Miniflux 2.2.15 with default configuration (media proxy enabled by default: MEDIA_PROXY_MODE=http-only).

  2. Log in with any normal user account.

  3. Subscribe to a feed you control that contains an entry with an image URL pointing to an internal address reachable from the Miniflux server, e.g.:

    • <img src="http://<internal-target>/secret"> (Note: <internal-target> must be reachable from the Miniflux process/network; in containerized setups, 127.0.0.1 may not refer to the host.)

  4. Open the entry and locate the rewritten media proxy URL (/proxy/<encodedDigest>/<encodedURL>) in the rendered HTML/page source.

  5. Request the /proxy/... URL. Expected (vulnerable): Miniflux fetches the internal URL and returns the internal response (SSRF).

Impact

Type: SSRF (Server-Side Request Forgery) via media proxy
Who is impacted: Miniflux instances with media proxy enabled (default configuration typically enables it for HTTP/mixed content handling).
Impact: attackers with a valid Miniflux account can fetch internal resources reachable from the Miniflux server (e.g., localhost services, private network services, and link-local endpoints such as 169.254.169.254), potentially exposing sensitive data.

Suggested CVSS (v3.1)

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

If there any questions or issues reproducing this, please contact: jeongwoolee340@gmail.com

Risk Scores
Base Score
6.5

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information.

Threat Intelligence
6.0

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
0.26%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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