CVE-2026-71246

Received Received - Intake

Server-Side Request Forgery in Pixelfed via ActivityPubFetchService

Publication date: 2026-08-05

Last updated on: 2026-08-10

Assigner: TuranSec

Description

Pixelfed's SearchController (behind the auth middleware) accepts a URL via its remote-search parameters and fetches it server-side through ActivityPubFetchService, whose validateUrl only blocks the literal hosts 127.0.0.1, localhost, and ::1 and requires https, without checking the resolved IP against private, internal, or link-local ranges (e.g. 169.254.169.254).

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-08-05

Last Modified

2026-08-10

Generated

2026-08-25

AI Q&A

2026-08-05

EPSS Evaluated

2026-08-24

NVD

CVE-2026-71246

EUVD

EUVD-2026-53319

Affected Vendors & Products

Vendor	Product	Version / Range
pixelfed	pixelfed	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-918	The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

Attack-Flow Graph

Executive Summary

This is a Server-Side Request Forgery (SSRF) vulnerability in Pixelfed. It allows authenticated users to make the server fetch remote URLs via ActivityPub. The server only blocks localhost and 127.0.0.1 but does not check for private or internal IP ranges. This creates a semi-blind SSRF where attackers can trigger requests to internal systems or specific endpoints.

Detection Guidance

Detecting this vulnerability requires checking Pixelfed's configuration for improper URL validation in the SearchController. Review server logs for unusual outbound requests to internal or private IP ranges from the application. Check if ActivityPubFetchService's validateUrl() function allows unsafe hosts like 127.0.0.1 or localhost without proper IP range checks.

Impact Analysis

An attacker could exploit this to access internal services, scan internal networks, or interact with other systems on behalf of the server. This may lead to data leaks, unauthorized actions, or further exploitation of internal resources. The impact depends on what services are accessible from the server.

Compliance Impact

This SSRF vulnerability could violate compliance requirements by allowing unauthorized access to sensitive data or systems. For GDPR, it may lead to breaches of personal data. For HIPAA, it could expose protected health information. Organizations must address this to maintain compliance.

Mitigation Strategies

Update Pixelfed to the latest version where this issue is patched. Disable remote-search functionality if unused. Ensure ActivityPubFetchService's validateUrl() strictly blocks all private, internal, and link-local IP ranges (e.g., 169.254.0.0/16, 10.0.0.0/8). Enable and enforce DNS validation to filter by allowed domains only.

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