Faraday affected by SSRF via protocol-relative URL host override in build_exclusive_url

Exploitation

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

CVSS

5.8 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N

EPSS

• CVE-2026-25765: 0.40% estimated exploitation activity in the next 30 days; percentile 34.19 (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.

Impact Faraday's buildexclusiveurl 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(), buildurl(), 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). The ./ prefix guard added in v2.9.2 (PR #1569) explicitly exempts URLs starting with /, so protocol-relative URLs bypass it entirely. Example: Patches Faraday v2.14.1 is patched against this security issue. All versions of Faraday up to 2.14.0 are affected. Workarounds NOTE: Upgrading to Faraday v2.14.1+ is the recommended action to mitigate this issue, however should that not be an…

Published by the source

9 Feb 2026, 20:37 UTC

Last modified by the source

12 Feb 2026, 14:22 UTC

Source last checked

26 Oct 2026, 15:51 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-33mh-2634-fwr2

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# Patch Next advisory brief: CVE-2026-25765

Advisory: Faraday affected by SSRF via protocol-relative URL host override in build_exclusive_url
IDs: CVE-2026-25765, GHSA-33mh-2634-fwr2
Record: https://patchnext.com/advisories/cve-2026-25765 (revision 1, source checked 26 Oct 2026, 15:51 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: faraday 2.14.1, 1.10.5. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems faraday: affected >= 2.0.0, <= 2.14.0; >= 1.0.0, <= 1.10.4; fixed in 1.10.5, 2.14.1

## Suggested inspection (read-only)
- RubyGems faraday: 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 faraday.
- 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-33mh-2634-fwr2 (GitHub-reviewed advisory GHSA-33mh-2634-fwr2 lists affected ranges: RubyGems faraday >=2.0.0 =1.0.0 <=1.10.4)

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