{"id":57780,"date":"2025-07-06T03:37:08","date_gmt":"2025-07-06T03:37:08","guid":{"rendered":""},"modified":"2025-08-09T23:04:16","modified_gmt":"2025-08-10T05:04:16","slug":"cve-2025-6916-critical-authentication-bypass-vulnerability-in-totolink-t6-4-1-5cu-748-b20211015","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-6916-critical-authentication-bypass-vulnerability-in-totolink-t6-4-1-5cu-748-b20211015\/","title":{"rendered":"CVE-2025-6916: Critical Authentication Bypass Vulnerability in TOTOLINK T6 4.1.5cu.748_B20211015<\/strong>"},"content":{"rendered":"

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

In the world of cybersecurity, few things are as unsettling as the discovery of a critical vulnerability. And that’s exactly what we’re dealing with in the case of CVE-2025-6916, a troubling flaw in the TOTOLINK T6 4.1.5cu.748_B20211015. This vulnerability affects a crucial function of the Form_Login file<\/a>, specifically the manipulation of the authCode\/goURL argument, leading to missing authentication. Given the severity of the vulnerability<\/a>, its implications are far-reaching, potentially affecting all users of this version of TOTOLINK T6. This is a matter of high concern as it opens up potential avenues for system compromise or data<\/a> leakage.<\/p>\n

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

CVE ID: CVE-2025-6916
\nSeverity: Critical (8.8 CVSS Severity Score)
\nAttack Vector: Network
\nPrivileges Required: None
\nUser Interaction: None
\nImpact: Potential system<\/a> compromise or data leakage<\/p>\n

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

Product | Affected Versions<\/p>\n

TOTOLINK T6 | 4.1.5cu.748_B20211015<\/p>\n

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

The vulnerability lies within the Form_Login file<\/a> and specifically targets the argument authCode\/goURL. The successful manipulation of this argument can lead to bypassing the authentication<\/a> process. This means that an attacker can gain unauthorized access<\/a> to the system without needing any valid credentials. The attack, however, needs to be initiated from within the local network.<\/p>\n

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

Below is a conceptual representation of how the vulnerability might be exploited. This does not represent an actual exploit but is designed to illustrate the potential danger of the vulnerability<\/a>.<\/p>\n

POST \/formLoginAuth.htm HTTP\/1.1\nHost: target.example.com\nContent-Type: application\/x-www-form-urlencoded\nauthCode=anyvalue&goURL=anyvalue<\/code><\/pre>\n
In this example, the attacker replaces the ‘authCode’ and ‘goURL’ parameters with arbitrary values, potentially bypassing the security checks in place and gaining unauthorized<\/a> access.<\/p>\n
Mitigation and Workaround<\/strong><\/p>\n
As a mitigation measure, users are advised to apply the vendor patch as soon as it is available. In the meantime, the use of a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as a temporary mitigation to prevent unauthorized access<\/a>. Regularly updating and patching systems, as well as implementing robust network security measures, can also help in reducing the risk of such vulnerabilities<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"
Overview In the world of cybersecurity, few things are as unsettling as the discovery of a critical vulnerability. And that’s exactly what we’re dealing with in the case of CVE-2025-6916, a troubling flaw in the TOTOLINK T6 4.1.5cu.748_B20211015. This vulnerability affects a crucial function of the Form_Login file, specifically the manipulation of the authCode\/goURL argument, […]<\/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":[75],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-57780","post","type-post","status-publish","format-standard","hentry","category-uncategorized","attack_vector-authentication-bypass"],"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