{"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":"CVE-2025-8939: Buffer Overflow Vulnerability in Tenda AC20 Leading to Potential System Compromise<\/strong>"},"content":{"rendered":"

Overview<\/strong><\/p>\n

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<\/a> routers are widely used, this vulnerability could have far-reaching consequences, impacting countless systems and networks worldwide. It’s even more critical as the exploit<\/a> details have been disclosed to the public, increasing the likelihood of potential attacks.<\/p>\n

Vulnerability Summary<\/strong><\/p>\n

CVE ID: CVE-2025-8939
\nSeverity: High (8.8 CVSS Severity Score)
\nAttack Vector: Remote
\nPrivileges Required: None
\nUser Interaction: None
\nImpact: System compromise<\/a> or data leakage<\/p>\n

Affected Products<\/strong><\/p>\n

Product | Affected Versions<\/p>\n

Tenda AC20<\/a> | Versions up to 16.03.08.12<\/p>\n

How the Exploit Works<\/strong><\/p>\n

The vulnerability exists due to improper handling<\/a> of the ‘shareSpeed’ parameter in the \/goform\/WifiGuestSet file. Attackers can manipulate this parameter to cause a buffer overflow<\/a> condition. This 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 dangerous and highly exploitable vulnerability<\/a>.<\/p>\n

Conceptual Example Code<\/strong><\/p>\n

The following is a conceptual example of how this vulnerability might be exploited. This example represents a malicious HTTP POST request to the vulnerable endpoint with a manipulated<\/a> ‘shareSpeed’ parameter:<\/p>\n

POST \/goform\/WifiGuestSet HTTP\/1.1\nHost: target.example.com\nContent-Type: application\/x-www-form-urlencoded\nshareSpeed=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA...<\/code><\/pre>\n
In the example above, the ‘shareSpeed’ parameter is overloaded with an excessively long string of ‘A’ characters, triggering a buffer overflow<\/a> condition. This conceptual example is for illustrative purposes only and does not represent an actual exploit.<\/p>\n
Mitigation Guidance<\/strong><\/p>\n
Users of the affected Tenda 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 potential exploits<\/a>. However, these measures should not replace the need for patching as soon as possible.<\/p>\n","protected":false},"excerpt":{"rendered":"
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 […]<\/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,"_monsterinsights_skip_tracking":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":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t