{"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":"<strong>CVE-2025-48865: Manipulation of X-Forwarded Headers in Fabio Prior to Version 1.6.6<\/strong>"},"content":{"rendered":"<p><strong>Overview<\/strong><\/p>\n<p>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 <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2024-45554-high-severity-memory-corruption-due-to-race-condition\/\"  data-wpil-monitor-id=\"58170\">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<p><strong>Vulnerability Summary<\/strong><\/p>\n<p>CVE ID: CVE-2025-48865<br \/>\nSeverity: High (CVSS: 9.1)<br \/>\nAttack Vector: Network<br \/>\nPrivileges Required: None<br \/>\nUser Interaction: None<br \/>\nImpact: <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-32309-potential-system-compromise-due-to-remote-file-inclusion-in-php-program\/\"  data-wpil-monitor-id=\"56580\">Potential system compromise<\/a> or data leakage<\/p>\n<p><strong>Affected Products<\/strong><\/p><div id=\"ameeb-3930330704\" class=\"ameeb-content-2 ameeb-entity-placement\"><div style=\"border-left: 4px solid #555; padding-left: 20px; margin: 48px 0; font-family: Roboto, sans-serif; color: #ffffff; line-height: 1.6; max-width: 720px;\">\r\n  <h2 style=\"margin-top: 0; font-size: 22px; font-weight: 600; display: flex; align-items: center; letter-spacing: -0.02em;\">\r\n    <a href=\"https:\/\/www.ameeba.com\/chat\" style=\"display: inline-flex; align-items: center; margin-right: 10px;\">\r\n      <img decoding=\"async\" src=\"https:\/\/www.ameeba.com\/blog\/wp-content\/uploads\/2025\/10\/Best-App-icon-Ameeba.png\" alt=\"Ameeba Chat Icon\" style=\"width: 42px; height: 42px;\" \/>\r\n    <\/a>\r\n    Share secrets securely\r\n  <\/h2>\r\n\r\n  <p style=\"margin-bottom: 14px; color: #d1d5db;\">\r\n    Ameeba is private infrastructure for communication and sensitive work built on encrypted identity instead of exposed corporate identity systems.\r\n  <\/p>\r\n\r\n  <p style=\"margin-bottom: 18px; color: #a1a1aa;\">\r\n    Passwords, credentials, confidential files, screenshots, internal discussions, sensitive AI context, and private coordination should not become exposed across ordinary communication platforms.\r\n  <\/p>\r\n\r\n  <ul style=\"list-style: none; padding-left: 0; margin-bottom: 24px; color: #e4e4e7;\">\r\n    <li style=\"margin-bottom: 8px;\">\u2022 Encrypted identity<\/li>\r\n    <li style=\"margin-bottom: 8px;\">\u2022 Private Spaces for organizations and teams<\/li>\r\n    <li style=\"margin-bottom: 8px;\">\u2022 End-to-end encrypted chat, calls, files, and notes<\/li>\r\n    <li style=\"margin-bottom: 8px;\">\u2022 Sensitive AI work and protected collaboration<\/li>\r\n    <li>\u2022 Built for information that cannot leak<\/li>\r\n  <\/ul>\r\n\r\n  <p style=\"font-style: italic; font-weight: 600; margin-bottom: 24px; color: #ffffff;\">\r\n    Our mission is to secure human work alongside AI.\r\n  <\/p>\r\n\r\n  <div style=\"display: flex; flex-wrap: wrap; gap: 12px;\">\r\n    <a href=\"https:\/\/www.ameeba.com\/chat\/download\" style=\"background-color: #ffffff; color: #000000; padding: 10px 20px; text-decoration: none; border-radius: 8px; font-weight: 500;\">\r\n      Download Ameeba\r\n    <\/a>\r\n\r\n    <a href=\"https:\/\/www.ameeba.com\/chat\" style=\"border: 1px solid #ffffff; color: #ffffff; padding: 10px 20px; text-decoration: none; border-radius: 8px; font-weight: 500;\">\r\n      Learn More\r\n    <\/a>\r\n  <\/div>\r\n<\/div><\/div>\n<p>Product | Affected Versions<\/p>\n<p>Fabio | Prior to 1.6.6<\/p>\n<p><strong>How the Exploit Works<\/strong><\/p>\n<p>The exploit takes advantage of a weakness in how Fabio processes hop-by-hop headers. Fabio adds <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-6162-critical-buffer-overflow-vulnerability-in-totolink-ex1200t-http-post-request-handler\/\"  data-wpil-monitor-id=\"64753\">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, <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-27010-path-traversal-vulnerability-in-bslthemes-tastyc-leading-to-php-local-file-inclusion\/\"  data-wpil-monitor-id=\"55838\">leading to potential security vulnerabilities<\/a>. This attack leverages the behavior that <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-30256-denial-of-service-vulnerability-in-tenda-ac6-s-http-header-parsing-functionality\/\"  data-wpil-monitor-id=\"86862\">headers can be defined as hop-by-hop via the HTTP<\/a> Connection header.<\/p>\n<p><strong>Conceptual Example Code<\/strong><\/p><div id=\"ameeb-656467603\" class=\"ameeb-content ameeb-entity-placement\"><div class=\"poptin-embedded\" data-id=\"f6b387694f681\"><\/div>\r\n\r\n\r\n\r\n\r\n\r\n<\/div>\n<p>Here&#8217;s a conceptual example of how the <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-4366-request-smuggling-vulnerability-in-pingora-s-proxying-framework\/\"  data-wpil-monitor-id=\"56579\">vulnerability might be exploited via an HTTP request<\/a>:<\/p>\n<pre><code class=\"\" data-line=\"\">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{ &quot;data&quot;: &quot;...&quot; }<\/code><\/pre>\n<p>In this example, an attacker manipulates the &#8216;X-Forwarded-Host&#8217; header to redirect the traffic to a malicious server, <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2021-47669-linux-kernel-vulnerability-allowing-potential-system-compromise\/\"  data-wpil-monitor-id=\"58120\">potentially compromising the system<\/a> or leading to data leakage.<\/p>\n<p><strong>Mitigation<\/strong><\/p>\n<p>Users of Fabio are strongly recommended to update to version 1.6.6 or later, which <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-52890-critical-acl-bypass-vulnerability-in-incus-system-container-and-virtual-machine-manager\/\"  data-wpil-monitor-id=\"64752\">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":"<p>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 [&hellip;]<\/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,"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":[],"_links":{"self":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/49055","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/comments?post=49055"}],"version-history":[{"count":6,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/49055\/revisions"}],"predecessor-version":[{"id":79703,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/49055\/revisions\/79703"}],"wp:attachment":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/media?parent=49055"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/categories?post=49055"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/tags?post=49055"},{"taxonomy":"vendor","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/vendor?post=49055"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/product?post=49055"},{"taxonomy":"attack_vector","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/attack_vector?post=49055"},{"taxonomy":"asset_type","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/asset_type?post=49055"},{"taxonomy":"severity","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/severity?post=49055"},{"taxonomy":"exploit_status","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/exploit_status?post=49055"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}