{"id":59606,"date":"2025-07-24T08:58:48","date_gmt":"2025-07-24T08:58:48","guid":{"rendered":""},"modified":"2025-10-02T09:38:27","modified_gmt":"2025-10-02T15:38:27","slug":"cve-2025-40776-cache-poisoning-attack-vulnerability-in-bind-9","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-40776-cache-poisoning-attack-vulnerability-in-bind-9\/","title":{"rendered":"<strong>CVE-2025-40776: Cache-Poisoning Attack Vulnerability in BIND 9<\/strong>"},"content":{"rendered":"<p><strong>Overview<\/strong><\/p>\n<p>In this post, we will be discussing the grave vulnerability identified as CVE-2025-40776, which affects the `named` caching resolver configured to deploy EDNS Client Subnet (ECS) options. This vulnerability has a significant impact on BIND 9 versions, thereby posing a serious threat to organizations worldwide. The severity of this <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-45346-sql-injection-vulnerability-in-bacula-web-resulting-in-potential-system-compromise\/\"  data-wpil-monitor-id=\"68107\">vulnerability emerges from its potential to compromise entire systems<\/a> or leak sensitive data, which can have devastating ramifications for businesses, particularly those handling large volumes of sensitive data.<\/p>\n<p><strong>Vulnerability Summary<\/strong><\/p>\n<p>CVE ID: CVE-2025-40776<br \/>\nSeverity: High (CVSS 8.6)<br \/>\nAttack Vector: Network<br \/>\nPrivileges Required: None<br \/>\nUser Interaction: None<br \/>\nImpact: <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-7837-critical-vulnerability-in-totolink-t6-potentially-leading-to-system-compromise\/\"  data-wpil-monitor-id=\"71154\">Potential system<\/a> compromise or data leakage<\/p>\n<p><strong>Affected Products<\/strong><\/p><div id=\"ameeb-1883807464\" 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: 700px;\">\r\n  <h2 style=\"margin-top: 0; font-size: 20px; font-weight: 600; display: flex; align-items: center;\">\r\n    <a href=\"https:\/\/www.ameeba.com\/chat\" style=\"display: inline-flex; align-items: center; margin-right: 8px;\">\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: 40px; height: 40px;\" \/>\r\n    <\/a>\r\n    A new way to communicate\r\n  <\/h2>\r\n\r\n  <p style=\"margin-bottom: 12px;\">\r\n    Ameeba Chat is built on encrypted identity, not personal profiles.\r\n  <\/p>\r\n\r\n  <p style=\"margin-bottom: 16px;\">\r\n    Message, call, share files, and coordinate with identities kept separate.\r\n  <\/p>\r\n\r\n  <ul style=\"list-style: none; padding-left: 0; margin-bottom: 20px;\">\r\n    <li>\u2022 Encrypted identity<\/li>\r\n    <li>\u2022 Ameeba Chat authenticates access<\/li>\r\n    <li>\u2022 Aliases and categories<\/li>\r\n    <li>\u2022 End-to-end encrypted chat, calls, and files<\/li>\r\n    <li>\u2022 Secure notes for sensitive information<\/li>\r\n  <\/ul>\r\n\r\n  <p style=\"font-style: italic; font-weight: 600; margin-bottom: 24px;\">\r\n    Private communication, rethought.\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: 6px; font-weight: 500;\">Download Ameeba Chat<\/a>\r\n    <a href=\"https:\/\/www.ameeba.com\/chat\" style=\"border: 1px solid #ffffff; color: #ffffff; padding: 10px 20px; text-decoration: none; border-radius: 6px; font-weight: 500;\">Learn More<\/a>\r\n  <\/div>\r\n<\/div>\r\n<\/div>\n<p>Product | Affected Versions<\/p>\n<p>BIND 9 | 9.11.3-S1 to 9.16.50-S1<br \/>\nBIND 9 | 9.18.11-S1 to 9.18.37-S1<br \/>\nBIND 9 | 9.20.9-S1 to 9.20.10-S1<\/p>\n<p><strong>How the Exploit Works<\/strong><\/p>\n<p>This exploit works by sending malicious <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-52362-critical-server-side-request-forgery-vulnerability-in-phproxy\/\"  data-wpil-monitor-id=\"71153\">requests to a vulnerable<\/a> caching resolver that has been configured to use EDNS Client Subnet (ECS) options. This, in turn, manipulates the caching mechanism of the resolver leading to incorrect <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-27052-memory-corruption-vulnerability-in-unix-clients-processing-data-packets\/\"  data-wpil-monitor-id=\"74117\">data being stored and served to the clients<\/a>. This form of attack is commonly known as a cache-poisoning attack, which can <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-30404-integer-overflow-vulnerability-in-executorch-resulting-in-potential-system-compromise\/\"  data-wpil-monitor-id=\"75962\">result in system<\/a> compromise or data leakage.<\/p>\n<p><strong>Conceptual Example Code<\/strong><\/p><div id=\"ameeb-717629815\" 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>Below is a conceptual example of a malicious DNS <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-52797-critical-cross-site-request-forgery-csrf-vulnerability-in-josepsitjar-storymap\/\"  data-wpil-monitor-id=\"79403\">request that could exploit this vulnerability<\/a>:<\/p>\n<pre><code class=\"\" data-line=\"\">GET \/dns-query?dns=AAABAAABAAAAAAAAA3d3dwdleGFtcGxlA2NvbQAAAQAB HTTP\/1.1\nHost: vulnerable-dns-resolver.example.com\nAccept: application\/dns-message\nX-Forwarded-For: malicious-ip-address<\/code><\/pre>\n<p>In this example, the <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2024-9408-server-side-request-forgery-attack-in-eclipse-glassfish\/\"  data-wpil-monitor-id=\"77231\">attacker sends a GET request<\/a> with a DNS query. The `X-Forwarded-For` header is used to <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-33054-insufficient-ui-warning-in-remote-desktop-client-opens-door-to-spoofing-attacks\/\"  data-wpil-monitor-id=\"68106\">spoof the client&#8217;s<\/a> IP address, tricking the DNS resolver into thinking the request is coming from a different source. This could <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-53693-critical-unsafe-reflection-vulnerability-in-sitecore-xm-and-xp-leading-to-cache-poisoning\/\"  data-wpil-monitor-id=\"87750\">lead to the cache<\/a> poisoning, as the resolver might end up storing and serving incorrect data.<br \/>\nTo mitigate the <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2024-25178-critical-luajit-vulnerability-puts-systems-at-risk-of-compromise\/\"  data-wpil-monitor-id=\"71155\">risk of this vulnerability<\/a>, it is recommended to apply the vendor-supplied patch or use WAF\/IDS as a temporary mitigation strategy. Regular patch management and monitoring of network activity can also help in identifying any unusual patterns that may signify an attack.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Overview In this post, we will be discussing the grave vulnerability identified as CVE-2025-40776, which affects the `named` caching resolver configured to deploy EDNS Client Subnet (ECS) options. This vulnerability has a significant impact on BIND 9 versions, thereby posing a serious threat to organizations worldwide. The severity of this vulnerability emerges from its potential [&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-59606","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\/59606","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=59606"}],"version-history":[{"count":7,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/59606\/revisions"}],"predecessor-version":[{"id":80558,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/59606\/revisions\/80558"}],"wp:attachment":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/media?parent=59606"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/categories?post=59606"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/tags?post=59606"},{"taxonomy":"vendor","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/vendor?post=59606"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/product?post=59606"},{"taxonomy":"attack_vector","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/attack_vector?post=59606"},{"taxonomy":"asset_type","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/asset_type?post=59606"},{"taxonomy":"severity","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/severity?post=59606"},{"taxonomy":"exploit_status","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/exploit_status?post=59606"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}