CVE-2024-45614
Description
A flaw was found in rubygem-puma. In affected versions, clients could clobber values set by intermediate proxies (such as X-Forwarded-For) by providing an underscore version of the same header (X-Forwarded_For). Any users relying on proxy set variables are affected. v6.4.3/v5.6.9 now discards any headers using underscores if the non-underscore version also exists. Effectively, allowing the proxy defined headers to always win. Users are advised to upgrade. As a mitigation, Nginx has an underscores_in_headers configuration variable to discard these headers at the proxy level. Any users that are implicitly trusting the proxy defined headers for security should immediately cease doing so until upgraded to the fixed versions.
Statement
This issue is classified as moderate severity rather than important because, while it allows clients to manipulate proxy-set headers like X-Forwarded-For, its exploitability depends on specific conditions. The vulnerability only affects applications that rely on these headers for security purposes, such as IP-based access controls or logging, and is mitigated by proper server configurations (e.g., using underscores_in_headers off in Nginx). Furthermore, it does not directly compromise the server's integrity or enable arbitrary code execution.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base 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 | 5.4 | 5.4 | 5.4 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | High | High | High |
| Privileges Required | None | None | None |
| User Interaction | None | None | None |
| Scope | Changed | Changed | Changed |
| Confidentiality | Low | Low | Low |
| Integrity Impact | Low | Low | Low |
| Availability Impact | None | None | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
NVD: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
Understanding the Weakness (CWE)
Access Control
Technical Impact: Bypass Protection Mechanism
Access control checks for specific user data or functionality can be bypassed.
Access Control
Technical Impact: Gain Privileges or Assume Identity
Horizontal escalation of privilege is possible (one user can view/modify information of another user).
Access Control
Technical Impact: Gain Privileges or Assume Identity
Vertical escalation of privilege is possible if the user-controlled key is actually a flag that indicates administrator status, allowing the attacker to gain administrative access.
Frequently Asked Questions
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