lostisland faraday up to 2.14.0 URL connection.rb build_exclusive_url server-side request forgery

Summaryinfo

A vulnerability was found in lostisland faraday up to 2.14.0. It has been declared as critical. This affects the function build_exclusive_url in the library lib/faraday/connection.rb of the component URL Handler. Such manipulation leads to server-side request forgery. This vulnerability is referenced as CVE-2026-25765. It is possible to launch the attack remotely. No exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in lostisland faraday up to 2.14.0. It has been rated as critical. Affected by this issue is the function build_exclusive_url in the library lib/faraday/connection.rb of the component URL Handler. The manipulation with an unknown input leads to a server-side request forgery vulnerability. Using CWE to declare the problem leads to 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. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Faraday is an HTTP client library abstraction layer that provides a common interface over many adapters. Prior to 2.14.1, Faraday's build_exclusive_url method (in lib/faraday/connection.rb) uses Ruby's URI#merge to combine the connection's base URL with a user-supplied path. Per RFC 3986, protocol-relative URLs (e.g. //evil.com/path) are treated as network-path references that override the base URL's host/authority component. This means that if any application passes user-controlled input to Faraday's get(), post(), build_url(), or other request methods, an attacker can supply a protocol-relative URL like //attacker.com/endpoint to redirect the request to an arbitrary host, enabling Server-Side Request Forgery (SSRF). This vulnerability is fixed in 2.14.1.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-25765 since 02/05/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 298451 (Linux Distros Unpatched Vulnerability : CVE-2026-25765), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 2.14.1 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch a6d3a3a0bf59c2ab307d0abd91bc126aef5561bc is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (298451) and CERT Bund (WID-SEC-2026-0552). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

• Open Source Fluentd

Productinfo

Vendor

• lostisland

Name

• faraday

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9
• 2.10
• 2.11
• 2.12
• 2.13
• 2.14.0

License

• open-source

Website

• Product: https://github.com/lostisland/faraday/

CPE 2.3info

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CPE 2.2info

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Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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