{"id":58375,"date":"2025-07-08T10:00:45","date_gmt":"2025-07-08T10:00:45","guid":{"rendered":""},"modified":"2025-09-27T15:20:30","modified_gmt":"2025-09-27T21:20:30","slug":"cve-2025-30376-heap-based-buffer-overflow-in-microsoft-office-excel-leading-to-potential-system-compromise","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-30376-heap-based-buffer-overflow-in-microsoft-office-excel-leading-to-potential-system-compromise\/","title":{"rendered":"<strong>CVE-2025-30376: Heap-based Buffer Overflow in Microsoft Office Excel Leading to Potential System Compromise<\/strong>"},"content":{"rendered":"<p><strong>Overview<\/strong><\/p>\n<p>CVE-2025-30376 is a high severity vulnerability present in Microsoft Office Excel. This vulnerability stems from a heap-based buffer overflow that could potentially allow unauthorized attackers to execute code locally on the victim&#8217;s system. It poses a significant threat to the security of sensitive data, as it may permit <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-43933-high-risk-vulnerability-leading-to-potential-system-compromise-via-password-reset-feature\/\"  data-wpil-monitor-id=\"70821\">system compromise<\/a> or data leakage.<br \/>\nThe <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-8028-critical-vulnerability-in-firefox-and-thunderbird-due-to-incorrect-computation-of-branch-address\/\"  data-wpil-monitor-id=\"73866\">vulnerability is of particular concern due<\/a> to the widespread usage of Microsoft Office Excel across industries and organizations of all sizes. The successful exploitation of this <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-52717-sql-injection-vulnerability-in-lifterlms-leads-to-potential-system-compromise\/\"  data-wpil-monitor-id=\"65373\">vulnerability could lead<\/a> to significant breaches, putting personal, financial, and business-critical information at risk.<\/p>\n<p><strong>Vulnerability Summary<\/strong><\/p>\n<p>CVE ID: CVE-2025-30376<br \/>\nSeverity: High &#8211; CVSS 7.8<br \/>\nAttack Vector: Local<br \/>\nPrivileges Required: None<br \/>\nUser Interaction: Required<br \/>\nImpact: <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-29331-critical-remote-code-execution-vulnerability-in-mhsanaei-3x-ui\/\"  data-wpil-monitor-id=\"64975\">Execution of unauthorized code<\/a> leading to potential system compromise or data leakage.<\/p>\n<p><strong>Affected Products<\/strong><\/p><div id=\"ameeb-2014253565\" 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><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=\"73093\">Microsoft Office<\/a> Excel | [Insert affected version]<\/p>\n<p><strong>How the Exploit Works<\/strong><\/p>\n<p>The <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-29977-use-after-free-vulnerability-in-microsoft-office-excel\/\"  data-wpil-monitor-id=\"64983\">vulnerability arises from a heap-based buffer overflow in Microsoft Office<\/a> Excel. An attacker can exploit this by crafting a malicious Excel document that, when opened, <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-24063-heap-based-buffer-overflow-vulnerability-in-windows-kernel\/\"  data-wpil-monitor-id=\"64985\">overflows the buffer<\/a> and allows the attacker to execute arbitrary code. This code execution happens within the security context of the current user, which could lead to unauthorized system access or data leakage if the <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-4334-critical-privilege-escalation-vulnerability-in-simple-user-registration-plugin-for-wordpress\/\"  data-wpil-monitor-id=\"64957\">user possesses elevated privileges<\/a>.<\/p>\n<p><strong>Conceptual Example Code<\/strong><\/p><div id=\"ameeb-2872328064\" 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>A conceptual exploit might involve a malicious macro embedded within an Excel document. Once the document is opened and the macro is executed, it can result in <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-6614-critical-buffer-overflow-vulnerability-in-d-link-dir-619l\/\"  data-wpil-monitor-id=\"64986\">buffer overflow<\/a>. Here&#8217;s a concept of how this might look:<\/p>\n<pre><code class=\"\" data-line=\"\">Sub MaliciousMacro()\nDim buffer As String\nDim overflow As String\n&#039; Fill the buffer with data\nbuffer = String(1, &quot;A&quot;)\n&#039; Create an overflow string longer than the buffer can handle\noverflow = String(2, &quot;B&quot;)\n&#039; Cause the buffer overflow, leading to potential arbitrary code execution\nbuffer = overflow\nEnd Sub<\/code><\/pre>\n<p><strong>Mitigation Guidance<\/strong><\/p>\n<p>Users are advised to apply the vendor patch as soon as it becomes available for their version of <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-47170-use-after-free-vulnerability-in-microsoft-office-word\/\"  data-wpil-monitor-id=\"75411\">Microsoft Office<\/a> Excel. As a temporary mitigation strategy, <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-31100-unrestricted-file-upload-leads-to-web-shell-deployment-in-mojoomla-school-management\/\"  data-wpil-monitor-id=\"84687\">deploying a Web<\/a> Application Firewall (WAF) or Intrusion Detection System (IDS) can help detect and prevent exploitation attempts. Additionally, it is recommended to exercise caution when <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-58158-harness-open-source-git-lfs-server-vulnerability\/\"  data-wpil-monitor-id=\"85523\">opening Excel documents from untrusted sources<\/a> and to disable macros by default.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Overview CVE-2025-30376 is a high severity vulnerability present in Microsoft Office Excel. This vulnerability stems from a heap-based buffer overflow that could potentially allow unauthorized attackers to execute code locally on the victim&#8217;s system. It poses a significant threat to the security of sensitive data, as it may permit system compromise or data leakage. The [&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":[82],"product":[],"attack_vector":[86,80],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-58375","post","type-post","status-publish","format-standard","hentry","category-uncategorized","vendor-microsoft","attack_vector-buffer-overflow","attack_vector-rce"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/58375","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=58375"}],"version-history":[{"count":12,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/58375\/revisions"}],"predecessor-version":[{"id":78319,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/58375\/revisions\/78319"}],"wp:attachment":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/media?parent=58375"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/categories?post=58375"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/tags?post=58375"},{"taxonomy":"vendor","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/vendor?post=58375"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/product?post=58375"},{"taxonomy":"attack_vector","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/attack_vector?post=58375"},{"taxonomy":"asset_type","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/asset_type?post=58375"},{"taxonomy":"severity","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/severity?post=58375"},{"taxonomy":"exploit_status","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/exploit_status?post=58375"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}