CVE-2026-24427: Tenda AC7 Router Information Disclosure

CVE-2026-24427 Overview

CVE-2026-24427 is a Sensitive Data Exposure vulnerability affecting Shenzhen Tenda AC7 routers running firmware version V03.03.03.01_cn and prior. The vulnerability allows attackers to obtain administrative credentials through plaintext exposure in web management configuration responses. This information disclosure flaw is compounded by improper Cache-Control header implementation, potentially allowing cached credentials to be retrieved by attackers with local system access.

Critical Impact

Administrative router credentials including the admin panel password are exposed in plaintext within configuration response bodies, enabling complete router compromise if exploited.

Affected Products

• Shenzhen Tenda AC7 firmware version V03.03.03.01_cn
• Shenzhen Tenda AC7 firmware versions prior to V03.03.03.01_cn

Discovery Timeline

• 2026-02-03 - CVE-2026-24427 published to NVD
• 2026-02-04 - Last updated in NVD database

Technical Details for CVE-2026-24427

Vulnerability Analysis

This vulnerability falls under CWE-201 (Insertion of Sensitive Information Into Sent Data), representing a significant information disclosure weakness in the Tenda AC7 router's web management interface. The core issue stems from the router's configuration API endpoints returning sensitive administrative credentials in plaintext within HTTP response bodies.

When users or administrators interact with the router's web management interface, certain configuration endpoints include the router's admin password directly in the response data. This design flaw means that any process or attacker capable of intercepting these HTTP responses can trivially extract the administrative credentials without requiring any authentication bypass or cryptographic attack.

The vulnerability's impact is further amplified by the absence of proper Cache-Control directives in the HTTP responses. Without headers such as Cache-Control: no-store or Cache-Control: no-cache, web browsers may cache pages containing the exposed credentials. This creates a secondary attack vector where an attacker with access to the client system, browser profile, or browser cache can retrieve these cached credentials even after the original session has ended.

Root Cause

The root cause of this vulnerability is twofold:

1. Improper Data Handling: The firmware's web management module includes sensitive credential information directly in configuration API responses without any obfuscation, encryption, or access control verification. This violates the principle of least privilege and secure data handling practices.

2. Missing Security Headers: The web server configuration fails to implement appropriate HTTP cache control headers, allowing browsers to persist sensitive response data in local cache storage.

Attack Vector

The attack requires local access to exploit this vulnerability. An attacker must either be able to intercept HTTP traffic between the administrator's browser and the router, or have access to the client system where cached credentials may be stored. Attack scenarios include:

• Browser Cache Exploitation: An attacker with physical or remote access to a system that previously accessed the router's management interface can examine browser cache files to extract the plaintext credentials.

• Shared Computer Scenario: In environments where multiple users share a workstation (public terminals, shared office computers), subsequent users may access cached configuration pages containing admin credentials.

• Local Network Interception: An attacker on the same local network segment could potentially intercept unencrypted HTTP management traffic to capture credential-containing responses.

The vulnerability mechanism involves the router's web management interface embedding administrative credentials directly within configuration response payloads. When an administrator accesses certain configuration pages, the server responds with JSON or HTML content that includes the plaintext password. Combined with missing cache-control headers, these responses may be stored by the browser and persist on disk. For detailed technical analysis, refer to the VulnCheck Advisory on Tenda AC7.

Detection Methods for CVE-2026-24427

Indicators of Compromise

• Presence of plaintext router credentials in browser cache directories (~/.cache/, browser profile folders)
• HTTP response logs showing configuration endpoints returning password fields in plaintext
• Unusual administrative login activity from unexpected client systems or IP addresses
• Evidence of browser cache enumeration tools or scripts on client systems

Detection Strategies

• Monitor network traffic to/from Tenda AC7 routers for configuration requests containing credential data in responses
• Implement endpoint detection rules to identify access to browser cache locations associated with router management sessions
• Deploy network intrusion detection signatures to flag HTTP responses from router management interfaces containing password fields
• Review web server access logs for abnormal frequency of configuration endpoint requests

Monitoring Recommendations

• Enable logging on the Tenda AC7 router if supported to track administrative access attempts
• Implement network segmentation to isolate router management interfaces from general user traffic
• Deploy Security Information and Event Management (SIEM) rules to correlate administrative login events with potential cache access indicators
• Conduct periodic security audits of client systems that have accessed router management interfaces

How to Mitigate CVE-2026-24427

Immediate Actions Required

• Restrict access to the router's web management interface to trusted systems only
• Clear browser cache on all systems that have previously accessed the Tenda AC7 management interface
• Change administrative credentials immediately and avoid accessing the management interface until a patch is available
• Consider disabling remote web management and use local console access where possible

Patch Information

As of the last update on 2026-02-04, no official patch has been released by Tenda for this vulnerability. Organizations should monitor the Tenda AC7 Product Page for firmware updates addressing this security issue.

Workarounds

• Configure client browsers to disable caching when accessing router management interfaces using private/incognito browsing modes
• Implement network-level access controls (firewall rules, VLANs) to limit which hosts can reach the router's management interface
• Use a dedicated, hardened administrative workstation for router management that is not shared with other users
• Consider deploying a reverse proxy with proper security headers in front of the management interface if technically feasible

# Browser cache clearing example (Linux)
# Clear browser cache directories after administrative sessions
rm -rf ~/.cache/chromium/Default/Cache/*
rm -rf ~/.cache/mozilla/firefox/*.default/cache2/*

# Network isolation example using iptables
# Restrict management interface access to specific admin IP
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.100 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP