CVE-2026-33637
Description
A flaw was found in Faraday, an HTTP client library. This vulnerability allows a remote attacker to perform off-host request forgery by exploiting a protocol-relative host override when a request target is passed as a URI object. This can redirect a request from a fixed-base Faraday connection to an attacker-controlled host, potentially exposing sensitive information such as Authorization headers and default query parameters.
Statement
Red Hat products include the Faraday Ruby gem as an indirect dependency. This vulnerability allows off-host request forgery when a request target is passed as a URI object rather than a String to Faraday::Connection#build_exclusive_url. Exploitation requires the application to construct Faraday requests using URI objects with attacker-controlled input, which limits the exposure in typical Red Hat product usage.
Mitigation
Ensure that request targets passed to Faraday connections use String types rather than URI objects. Validate and sanitize all user-controlled input before using it to construct HTTP request targets.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.3 | 6.5 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | Low | N/A |
| Privileges Required | Low | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Changed | Unchanged | N/A |
| Confidentiality | High | Low | N/A |
| Integrity Impact | None | Low | N/A |
| Availability Impact | None | None | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data
Integrity
Technical Impact: Execute Unauthorized Code or Commands
Access Control
Technical Impact: Bypass Protection Mechanism
By providing URLs to unexpected hosts or ports, attackers can make it appear that the server is sending the request, possibly bypassing access controls such as firewalls that prevent the attackers from accessing the URLs directly. The server can be used as a proxy to conduct port scanning of hosts in internal networks, use other URLs such as that can access documents on the system (using file://), or use other protocols such as gopher:// or tftp://, which may provide greater control over the contents of requests.
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