CVE-2025-61780
Description
A potential information disclosure vulnerability has been identified in the RubyGem Rack affecting Rack::Sendfile when used behind a proxy that supports x-sendfile headers (e.g., Nginx). When processing untrusted x-sendfile-type or x-accel-mapping headers, the middleware could misinterpret them as proxy directives, causing the proxy to make unintended internal requests. An attacker could exploit this by sending crafted headers and requesting paths that trigger proxy-based acceleration, potentially accessing internal application endpoints that are normally protected. The issue does not allow arbitrary file reads, code execution, or denial of service.
Statement
This vulnerability is classified as Moderate severity primarily because exploitation requires a specific deployment scenario meeting all of the following conditions:
The application must use Rack::Sendfile behind a proxy that supports x-accel-redirect (eg. Nginx)
The proxy must not consistently set or remove the relevant x-sendfile-type and x-accel-mapping headers
The application must expose endpoints returning objects responding to .to_path.
Exploitation could allow attackers to bypass proxy-enforced access controls and reach internal routes.
CVSS Assessment:
Scope (S:C): Changed — the attack affects the proxy's interpretation of internal routes, which is outside the original application scope.
Confidentiality (C:L): Low — attacker can only see internal endpoints, but does not allow arbitrary file access or sensitive data exposure.
Affectedness:
Ruby 2.x and 3.x versions shipped with Red Hat Enterprise Linux, Red Hat Openshift Core OS (RHOCS) and Red Hat In-Vehicle OS (RHIVOS) are not affected, as they do not bundle the rack RubyGem by default. Rack is a third-party gem that must be installed separately.
Mitigation
No mitigation is currently available that meets Red Hat Product Security's standards for usability, deployment, applicability, or stability.
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 | 5.8 | 5.3 | 5.8 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | Low | Low | Low |
| Privileges Required | None | None | None |
| User Interaction | None | None | None |
| Scope | Changed | Unchanged | Changed |
| Confidentiality | Low | Low | Low |
| Integrity Impact | None | None | None |
| Availability Impact | None | None | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
Understanding the Weakness (CWE)
Integrity,Non-Repudiation,Access Control
Technical Impact: Unexpected State; Hide Activities; Bypass Protection Mechanism
An attacker could create HTTP messages to exploit a number of weaknesses including 1) the message can trick the web server to associate a URL with another URL's webpage and caching the contents of the webpage (web cache poisoning attack), 2) the message can be structured to bypass the firewall protection mechanisms and gain unauthorized access to a web application, and 3) the message can invoke a script or a page that returns client credentials (similar to a Cross Site Scripting attack).
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