{"id":58043,"date":"2025-07-07T10:50:17","date_gmt":"2025-07-07T10:50:17","guid":{"rendered":""},"modified":"2025-08-31T18:38:23","modified_gmt":"2025-09-01T00:38:23","slug":"cve-2025-29979-heap-based-buffer-overflow-vulnerability-in-microsoft-office-excel","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-29979-heap-based-buffer-overflow-vulnerability-in-microsoft-office-excel\/","title":{"rendered":"<strong>CVE-2025-29979: Heap-based Buffer Overflow Vulnerability in Microsoft Office Excel<\/strong>"},"content":{"rendered":"<p><strong>Overview<\/strong><\/p>\n<p>The Common Vulnerabilities and Exposures (CVE) system has cataloged a significant security flaw in Microsoft Office Excel, identified as CVE-2025-29979. This vulnerability is a heap-based buffer overflow issue, which could allow an unauthorized attacker to execute code locally on an affected system. Given the widespread use of <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-29978-use-after-free-vulnerability-in-microsoft-office-powerpoint-allowing-unauthorized-local-code-execution\/\"  data-wpil-monitor-id=\"64867\">Microsoft Office<\/a> Excel, this vulnerability presents a significant risk to many organizations and individual users. It is especially concerning because it could <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-3090-unauthenticated-remote-attack-leading-to-potential-data-leakage-and-system-compromise\/\"  data-wpil-monitor-id=\"64574\">potentially lead to a full system compromise or data leakage<\/a>.<\/p>\n<p><strong>Vulnerability Summary<\/strong><\/p>\n<p>CVE ID: CVE-2025-29979<br \/>\nSeverity: High (7.8 CVSS Score)<br \/>\nAttack Vector: Local<br \/>\nPrivileges Required: Low<br \/>\nUser Interaction: Required<br \/>\nImpact: <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-6435-firefox-vulnerability-leading-to-potential-system-compromise-and-data-leakage\/\"  data-wpil-monitor-id=\"64822\">System compromise or data<\/a> leakage<\/p>\n<p><strong>Affected Products<\/strong><\/p><div id=\"ameeb-1117280180\" 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><a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-29976-improper-privilege-management-vulnerability-in-microsoft-office-sharepoint\/\"  data-wpil-monitor-id=\"64899\">Microsoft Office<\/a> Excel | All versions prior to vendor patch<\/p>\n<p><strong>How the Exploit Works<\/strong><\/p>\n<p>This <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-36038-remote-code-execution-vulnerability-in-ibm-websphere-application-server\/\"  data-wpil-monitor-id=\"64679\">vulnerability occurs due to the application&#8217;s<\/a> failure to properly manage memory when processing certain data within an Excel spreadsheet. If manipulated correctly, this flaw can lead to a heap-based <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-6616-critical-buffer-overflow-vulnerability-in-d-link-dir-619l-2-06b01\/\"  data-wpil-monitor-id=\"64650\">buffer overflow<\/a>, enabling an attacker to execute arbitrary code on the affected system. The attacker would need to craft a malicious Excel file and convince the victim to open it.<\/p>\n<p><strong>Conceptual Example Code<\/strong><\/p><div id=\"ameeb-1179155052\" 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 exact exploit <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-20281-critical-vulnerability-in-cisco-ise-and-ise-pic-apis-allows-remote-code-execution\/\"  data-wpil-monitor-id=\"64608\">code would be specific to the vulnerability<\/a> and the attacker&#8217;s intent, a conceptual example might involve embedding a malicious macro within an Excel file.<\/p>\n<pre><code class=\"\" data-line=\"\">Sub Auto_Open()\nShell(&quot;cmd.exe \/C arbitrary_code_here&quot;, vbHide)\nEnd Sub<\/code><\/pre>\n<p>In this example, the `Shell` function is used to initiate a command prompt (`cmd.exe`) that executes the attacker&#8217;s <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2021-4457-critical-unauthenticated-arbitrary-file-upload-vulnerability-in-zoomsounds-plugin\/\"  data-wpil-monitor-id=\"64701\">arbitrary code when the Excel file<\/a> is opened. This is a simplistic example and real-world exploits might be more complex and obfuscated to evade detection.<\/p>\n<p><strong>Recommended Mitigation<\/strong><\/p>\n<p>The primary mitigation for this vulnerability is to apply the vendor-provided patch. This will correct the <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-6543-critical-memory-overflow-vulnerability-in-netscaler-adc-and-gateway\/\"  data-wpil-monitor-id=\"64573\">memory management issue and eliminate the related buffer overflow vulnerability<\/a>. As an interim measure, users can implement a Web Application Firewall (WAF) or Intrusion Detection System (IDS) to <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-20217-denial-of-service-vulnerability-in-snort-3-detection-engine-of-cisco-secure-firewall-threat-defense-software\/\"  data-wpil-monitor-id=\"77115\">detect and block attempts to exploit this vulnerability<\/a>. However, this should not be considered a long-term solution, as it does not address the underlying flaw.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Overview The Common Vulnerabilities and Exposures (CVE) system has cataloged a significant security flaw in Microsoft Office Excel, identified as CVE-2025-29979. This vulnerability is a heap-based buffer overflow issue, which could allow an unauthorized attacker to execute code locally on an affected system. Given the widespread use of Microsoft Office Excel, this vulnerability presents a [&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],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-58043","post","type-post","status-publish","format-standard","hentry","category-uncategorized","vendor-microsoft","attack_vector-buffer-overflow"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/58043","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=58043"}],"version-history":[{"count":9,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/58043\/revisions"}],"predecessor-version":[{"id":69489,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/58043\/revisions\/69489"}],"wp:attachment":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/media?parent=58043"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/categories?post=58043"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/tags?post=58043"},{"taxonomy":"vendor","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/vendor?post=58043"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/product?post=58043"},{"taxonomy":"attack_vector","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/attack_vector?post=58043"},{"taxonomy":"asset_type","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/asset_type?post=58043"},{"taxonomy":"severity","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/severity?post=58043"},{"taxonomy":"exploit_status","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/exploit_status?post=58043"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}