{"id":49055,"date":"2025-06-05T15:27:41","date_gmt":"2025-06-05T15:27:41","guid":{"rendered":""},"modified":"2025-10-01T14:40:43","modified_gmt":"2025-10-01T20:40:43","slug":"cve-2025-48865-manipulation-of-x-forwarded-headers-in-fabio-prior-to-version-1-6-6","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-48865-manipulation-of-x-forwarded-headers-in-fabio-prior-to-version-1-6-6\/","title":{"rendered":"CVE-2025-48865: Manipulation of X-Forwarded Headers in Fabio Prior to Version 1.6.6<\/strong>"},"content":{"rendered":"

Overview<\/strong><\/p>\n

The Common Vulnerabilities and Exposures (CVE) system has recently identified a high-severity security vulnerability, CVE-2025-48865, that can potentially compromise systems or lead to data leakage. This vulnerability affects applications deployed using Fabio, an HTTP(S) and TCP router managed by consul. The vulnerability, which arises from the way Fabio processes hop-by-hop headers, is especially concerning due to its high CVSS severity<\/a> score of 9.1 and the wide usage of Fabio as a routing mechanism in various applications.<\/p>\n

Vulnerability Summary<\/strong><\/p>\n

CVE ID: CVE-2025-48865
\nSeverity: High (CVSS: 9.1)
\nAttack Vector: Network
\nPrivileges Required: None
\nUser Interaction: None
\nImpact: Potential system compromise<\/a> or data leakage<\/p>\n

Affected Products<\/strong><\/p>\n

Product | Affected Versions<\/p>\n

Fabio | Prior to 1.6.6<\/p>\n

How the Exploit Works<\/strong><\/p>\n

The exploit takes advantage of a weakness in how Fabio processes hop-by-hop headers. Fabio adds HTTP headers like X-Forwarded-Host and X-Forwarded-Port when routing requests<\/a> to backend applications. These headers are trusted by the receiving application. However, due to the vulnerability, an attacker can remove or modify these headers, leading to potential security vulnerabilities<\/a>. This attack leverages the behavior that headers can be defined as hop-by-hop via the HTTP<\/a> Connection header.<\/p>\n

Conceptual Example Code<\/strong><\/p>\n

Here’s a conceptual example of how the vulnerability might be exploited via an HTTP request<\/a>:<\/p>\n

POST \/vulnerable\/endpoint HTTP\/1.1\nHost: target.example.com\nConnection: close, X-Forwarded-Host\nX-Forwarded-Host: malicious.com\nContent-Type: application\/json\n{ \"data\": \"...\" }<\/code><\/pre>\n
In this example, an attacker manipulates the ‘X-Forwarded-Host’ header to redirect the traffic to a malicious server, potentially compromising the system<\/a> or leading to data leakage.<\/p>\n
Mitigation<\/strong><\/p>\n
Users of Fabio are strongly recommended to update to version 1.6.6 or later, which contains a patch for this vulnerability<\/a>. If updating is not immediately possible, a temporary mitigation can be to use a Web Application Firewall (WAF) or Intrusion Detection System (IDS) to monitor and block any suspicious activity related to the manipulation of X-Forwarded headers.<\/p>\n","protected":false},"excerpt":{"rendered":"
Overview The Common Vulnerabilities and Exposures (CVE) system has recently identified a high-severity security vulnerability, CVE-2025-48865, that can potentially compromise systems or lead to data leakage. This vulnerability affects applications deployed using Fabio, an HTTP(S) and TCP router managed by consul. The vulnerability, which arises from the way Fabio processes hop-by-hop headers, is especially concerning […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[1],"tags":[],"vendor":[],"product":[],"attack_vector":[],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-49055","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t