{"id":64174,"date":"2025-08-19T18:58:25","date_gmt":"2025-08-19T18:58:25","guid":{"rendered":""},"modified":"2025-09-27T02:05:16","modified_gmt":"2025-09-27T08:05:16","slug":"cve-2025-8760-critical-buffer-overflow-vulnerability-in-instar-2k-and-4k-3-11-1-build-1124","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-8760-critical-buffer-overflow-vulnerability-in-instar-2k-and-4k-3-11-1-build-1124\/","title":{"rendered":"<strong>CVE-2025-8760: Critical Buffer Overflow Vulnerability in INSTAR 2K+ and 4K 3.11.1 Build 1124<\/strong>"},"content":{"rendered":"<p><strong>Overview<\/strong><\/p>\n<p>A severe vulnerability, CVE-2025-8760, has been identified in INSTAR&#8217;s 2K+ and 4K 3.11.1 Build 1124. This particular vulnerability affects the base64_decode function of the fcgi_server component. By manipulating the &#8216;Authorization&#8217; argument, an attacker may cause a <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-7463-critical-buffer-overflow-vulnerability-in-tenda-fh1201-1-2-0-14\/\"  data-wpil-monitor-id=\"71815\">buffer overflow<\/a>. This <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-30327-integer-overflow-vulnerability-in-incopy-leading-to-potential-arbitrary-code-execution\/\"  data-wpil-monitor-id=\"73611\">vulnerability is significant due to its potential<\/a> for remote initiation, allowing attackers to potentially compromise systems or leak data from afar. Given its high severity score, it is crucial for <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-44955-critical-vulnerability-in-ruckus-network-director-allows-jail-users-to-gain-root-access\/\"  data-wpil-monitor-id=\"75991\">users and administrators to understand the nature of this vulnerability<\/a> and take appropriate action.<\/p>\n<p><strong>Vulnerability Summary<\/strong><\/p>\n<p>CVE ID: CVE-2025-8760<br \/>\nSeverity: Critical, CVSS score 9.8<br \/>\nAttack Vector: Network<br \/>\nPrivileges Required: None<br \/>\nUser Interaction: None<br \/>\nImpact: <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-27050-memory-corruption-vulnerability-leading-to-potential-system-compromise-and-data-leakage\/\"  data-wpil-monitor-id=\"74955\">Potential system compromise or data<\/a> leakage<\/p>\n<p><strong>Affected Products<\/strong><\/p><div id=\"ameeb-893956725\" 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>INSTAR 2K+ | 3.11.1 Build 1124<br \/>\nINSTAR 4K | 3.11.1 Build 1124<\/p>\n<p><strong>How the Exploit Works<\/strong><\/p>\n<p>This <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2024-13974-high-risk-business-logic-vulnerability-in-up2date-component-of-sophos-firewall\/\"  data-wpil-monitor-id=\"73893\">vulnerability exploits the base64_decode function in the fcgi_server component<\/a> of the affected INSTAR products. Specifically, an attacker can overly manipulate the &#8216;Authorization&#8217; argument, causing a <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-49691-heap-based-buffer-overflow-in-windows-media-leading-to-potential-system-compromise\/\"  data-wpil-monitor-id=\"72065\">buffer overflow<\/a>. A <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-49674-windows-rras-heap-based-buffer-overflow-vulnerability\/\"  data-wpil-monitor-id=\"72326\">buffer overflow<\/a> occurs when more data is written to a buffer than it can handle, causing it to overflow into adjacent memory spaces. In this case, the <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-8184-critical-stack-based-buffer-overflow-vulnerability-in-d-link-dir-513\/\"  data-wpil-monitor-id=\"71756\">buffer overflow can potentially overwrite critical<\/a> data or execute malicious code, leading to system compromise or data leakage.<\/p>\n<p><strong>Conceptual Example Code<\/strong><\/p><div id=\"ameeb-2821080870\" 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>While the specific exploit code is not available, below is a conceptual example of how an HTTP request might be <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-55746-unauthenticated-file-manipulation-vulnerability-in-directus\/\"  data-wpil-monitor-id=\"78743\">manipulated to exploit this vulnerability<\/a>:<\/p>\n<pre><code class=\"\" data-line=\"\">POST \/fcgi_server\/base64_decode HTTP\/1.1\nHost: target.example.com\nAuthorization: Basic [Overly long base64 encoded string]<\/code><\/pre>\n<p>In this example, the `[Overly long base64 encoded string]` represents a base64 string that, when decoded, is larger than the <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-9779-totolink-a702r-buffer-overflow-vulnerability-in-the-function-sub-4162dc\/\"  data-wpil-monitor-id=\"85115\">buffer in the base64_decode function<\/a> can handle. When the function attempts to decode this string, it causes a buffer overflow, potentially leading to <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-47168-use-after-free-vulnerability-in-microsoft-office-word-allowing-unauthorized-code-execution\/\"  data-wpil-monitor-id=\"73144\">unauthorized code<\/a> execution or other unintended behavior.<\/p>\n<p><strong>Mitigation Guidance<\/strong><\/p>\n<p>Customers using affected versions of INSTAR 2K+ and 4K are advised to apply the vendor patch as soon as it becomes available. In the absence of a patch, or as a temporary measure, a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) could be used to mitigate the vulnerability. These systems can be configured to <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-8059-critical-privilege-escalation-vulnerability-in-b-blocks-wordpress-plugin\/\"  data-wpil-monitor-id=\"76334\">block or alert on suspicious activity related to this vulnerability<\/a>, such as unusually large &#8216;Authorization&#8217; headers in HTTP requests to the fcgi_server component.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Overview A severe vulnerability, CVE-2025-8760, has been identified in INSTAR&#8217;s 2K+ and 4K 3.11.1 Build 1124. This particular vulnerability affects the base64_decode function of the fcgi_server component. By manipulating the &#8216;Authorization&#8217; argument, an attacker may cause a buffer overflow. This vulnerability is significant due to its potential for remote initiation, allowing attackers to potentially compromise [&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":[86],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-64174","post","type-post","status-publish","format-standard","hentry","category-uncategorized","attack_vector-buffer-overflow"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/64174","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=64174"}],"version-history":[{"count":12,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/64174\/revisions"}],"predecessor-version":[{"id":77902,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/64174\/revisions\/77902"}],"wp:attachment":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/media?parent=64174"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/categories?post=64174"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/tags?post=64174"},{"taxonomy":"vendor","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/vendor?post=64174"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/product?post=64174"},{"taxonomy":"attack_vector","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/attack_vector?post=64174"},{"taxonomy":"asset_type","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/asset_type?post=64174"},{"taxonomy":"severity","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/severity?post=64174"},{"taxonomy":"exploit_status","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/exploit_status?post=64174"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}