{"id":64227,"date":"2025-08-22T00:18:33","date_gmt":"2025-08-22T00:18:33","guid":{"rendered":""},"modified":"2025-10-22T21:12:57","modified_gmt":"2025-10-23T03:12:57","slug":"cve-2025-8939-buffer-overflow-vulnerability-in-tenda-ac20-leading-to-potential-system-compromise","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-8939-buffer-overflow-vulnerability-in-tenda-ac20-leading-to-potential-system-compromise\/","title":{"rendered":"<strong>CVE-2025-8939: Buffer Overflow Vulnerability in Tenda AC20 Leading to Potential System Compromise<\/strong>"},"content":{"rendered":"<p><strong>Overview<\/strong><\/p>\n<p>The CVE-2025-8939 is a cybersecurity vulnerability recently discovered in the Tenda AC20 up to 16.03.08.12. This flaw, found in an unidentified function of the file \/goform\/WifiGuestSet, can potentially enable remote attackers to compromise the system or leak data by exploiting a buffer overflow. As the <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-8810-critical-buffer-overflow-vulnerability-in-tenda-ac20-16-03-08-05\/\"  data-wpil-monitor-id=\"77799\">Tenda AC20<\/a> routers are widely used, this vulnerability could have far-reaching consequences, impacting countless systems and networks worldwide. It&#8217;s even more <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-41672-critical-cybersecurity-threat-exploiting-default-certificates\/\"  data-wpil-monitor-id=\"91276\">critical as the exploit<\/a> details have been disclosed to the public, increasing the likelihood of potential attacks.<\/p>\n<p><strong>Vulnerability Summary<\/strong><\/p>\n<p>CVE ID: CVE-2025-8939<br \/>\nSeverity: High (8.8 CVSS Severity Score)<br \/>\nAttack Vector: Remote<br \/>\nPrivileges Required: None<br \/>\nUser Interaction: None<br \/>\nImpact: <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-27055-memory-corruption-leads-to-potential-system-compromise-during-image-encoding\/\"  data-wpil-monitor-id=\"74149\">System compromise<\/a> or data leakage<\/p>\n<p><strong>Affected Products<\/strong><\/p><div id=\"ameeb-1168562025\" 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-2025-9087-stack-based-buffer-overflow-vulnerability-in-tenda-ac20-16-03-08-12\/\"  data-wpil-monitor-id=\"77808\">Tenda AC20<\/a> | Versions up to 16.03.08.12<\/p>\n<p><strong>How the Exploit Works<\/strong><\/p>\n<p>The <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-43193-critical-memory-handling-vulnerability-in-macos\/\"  data-wpil-monitor-id=\"71784\">vulnerability exists due to improper handling<\/a> of the &#8216;shareSpeed&#8217; parameter in the \/goform\/WifiGuestSet file. Attackers can manipulate this parameter to cause a <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=\"71783\">buffer overflow<\/a> condition. 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=\"73544\">overflow can then be leveraged to execute arbitrary code<\/a> on the system or access sensitive information. The attack can be launched remotely and does not require any form of user interaction, making it a <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-53213-unrestricted-upload-of-file-with-dangerous-type-vulnerability-in-woocommerce-multi-carrier-conditional-shipping-plugin\/\"  data-wpil-monitor-id=\"81759\">dangerous and highly exploitable vulnerability<\/a>.<\/p>\n<p><strong>Conceptual Example Code<\/strong><\/p><div id=\"ameeb-3310596446\" 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>The following is a conceptual example of how this vulnerability might be exploited. This example represents a malicious HTTP POST request to the <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-55746-unauthenticated-file-manipulation-vulnerability-in-directus\/\"  data-wpil-monitor-id=\"78741\">vulnerable endpoint with a manipulated<\/a> &#8216;shareSpeed&#8217; parameter:<\/p>\n<pre><code class=\"\" data-line=\"\">POST \/goform\/WifiGuestSet HTTP\/1.1\nHost: target.example.com\nContent-Type: application\/x-www-form-urlencoded\nshareSpeed=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA...<\/code><\/pre>\n<p>In the example above, the &#8216;shareSpeed&#8217; parameter is overloaded with an excessively long string of &#8216;A&#8217; characters, triggering 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=\"71813\">buffer overflow<\/a> condition. This conceptual example is for illustrative purposes only and does not represent an actual exploit.<\/p>\n<p><strong>Mitigation Guidance<\/strong><\/p>\n<p>Users of the affected Tenda <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2025-9006-critical-remote-buffer-overflow-vulnerability-in-tenda-ch22-1-0-0-1\/\"  data-wpil-monitor-id=\"75370\">AC20<\/a> routers are advised to apply the vendor-released patch immediately to remedy this vulnerability. In cases where immediate patching is not feasible, implementing Web Application Firewalls (WAFs) or Intrusion Detection Systems (IDS) can serve as temporary mitigation against <a href=\"https:\/\/www.ameeba.com\/blog\/cve-2024-7457-macos-authorization-model-exploit-leading-to-potential-mitm-attacks\/\"  data-wpil-monitor-id=\"79911\">potential exploits<\/a>. However, these measures should not replace the need for patching as soon as possible.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Overview The CVE-2025-8939 is a cybersecurity vulnerability recently discovered in the Tenda AC20 up to 16.03.08.12. This flaw, found in an unidentified function of the file \/goform\/WifiGuestSet, can potentially enable remote attackers to compromise the system or leak data by exploiting a buffer overflow. As the Tenda AC20 routers are widely used, this vulnerability could [&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-64227","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\/64227","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=64227"}],"version-history":[{"count":11,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/64227\/revisions"}],"predecessor-version":[{"id":84305,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/posts\/64227\/revisions\/84305"}],"wp:attachment":[{"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/media?parent=64227"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/categories?post=64227"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/tags?post=64227"},{"taxonomy":"vendor","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/vendor?post=64227"},{"taxonomy":"product","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/product?post=64227"},{"taxonomy":"attack_vector","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/attack_vector?post=64227"},{"taxonomy":"asset_type","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/asset_type?post=64227"},{"taxonomy":"severity","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/severity?post=64227"},{"taxonomy":"exploit_status","embeddable":true,"href":"https:\/\/www.ameeba.com\/blog\/wp-json\/wp\/v2\/exploit_status?post=64227"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}