CVE-2026-24437: Tenda W30e Information Disclosure Flaw

CVE-2026-24437 Overview

CVE-2026-24437 is a medium-severity information disclosure vulnerability affecting Shenzhen Tenda W30E V2 firmware. The vulnerability exists because the device's web interface serves sensitive administrative content without appropriate cache-control directives. As a result, browsers may store credential-bearing responses locally, exposing them to subsequent unauthorized access by other users who share the same device or gain access to browser cache storage.

This vulnerability falls under CWE-525 (Use of Web Browser Cache Containing Sensitive Information), a common weakness in embedded device web interfaces where security headers are improperly configured or omitted entirely.

Critical Impact

Local attackers with access to browser cache storage can retrieve cached administrative credentials and sensitive configuration data, potentially leading to full device compromise.

Affected Products

• Tenda W30E V2 Hardware
• Tenda W30E Firmware versions up to and including V16.01.0.19(5037)

Discovery Timeline

• 2026-01-26 - CVE-2026-24437 published to NVD
• 2026-01-28 - Last updated in NVD database

Technical Details for CVE-2026-24437

Vulnerability Analysis

This vulnerability represents a fundamental security misconfiguration in the Tenda W30E V2 router's web administration interface. When administrators access the device management portal, the server responds with sensitive pages containing credentials and configuration data but fails to include essential HTTP cache-control headers such as Cache-Control: no-store, Cache-Control: no-cache, or Pragma: no-cache.

Without these directives, web browsers follow their default caching behavior, storing response content including authentication tokens, session identifiers, and potentially plaintext credentials in local cache directories. An attacker with local access to the system where the administrator previously accessed the router can extract this cached content without requiring any authentication to the device itself.

The attack surface is particularly concerning in shared computing environments, public terminals, or scenarios where an attacker gains temporary physical access to an administrator's workstation. The cached credentials remain accessible until the browser cache is explicitly cleared or expires according to default browser policies.

Root Cause

The root cause of this vulnerability is the absence of proper HTTP response headers that instruct browsers not to cache sensitive administrative pages. The firmware's web server component does not implement security best practices for handling credential-bearing content, leaving sensitive data exposed in client-side storage mechanisms.

Specifically, the server fails to set:

• Cache-Control: no-store - Prevents any caching of the response
• Cache-Control: no-cache - Requires revalidation before using cached content
• Pragma: no-cache - Legacy header for HTTP/1.0 compatibility
• Expires: 0 - Marks content as immediately expired

Attack Vector

The attack requires local access to a system where an administrator has previously accessed the Tenda W30E V2 web interface. The attacker can exploit this vulnerability through several methods:

1. Browser Cache Inspection: Directly accessing browser cache directories on disk to extract cached HTML responses containing credentials
2. Browser Developer Tools: Using built-in developer tools to inspect cached resources if the browser session is still accessible
3. Cache Extraction Tools: Employing forensic or cache analysis utilities to systematically recover cached administrative content
4. Shared System Access: Logging into a shared workstation after an administrator has used it to manage the router

The vulnerability does not require network access to the router itself, only access to the cache storage of a system previously used for administration.

Detection Methods for CVE-2026-24437

Indicators of Compromise

• Unauthorized access to router administrative interface from unknown IP addresses
• Configuration changes to the Tenda W30E device that administrators did not authorize
• Evidence of browser cache extraction tools executed on administrative workstations
• Suspicious file access patterns targeting browser cache directories

Detection Strategies

• Monitor for access to browser cache directories on systems used for router administration
• Implement endpoint detection rules for cache extraction utilities and forensic tools
• Review router access logs for authentication from unusual client systems or at unexpected times
• Deploy file integrity monitoring on workstations to detect unauthorized cache access

Monitoring Recommendations

• Enable comprehensive logging on the Tenda W30E if supported by firmware
• Configure SIEM rules to correlate router administrative access with workstation security events
• Implement network segmentation monitoring to detect unauthorized device management traffic
• Establish baseline behavior for administrative access patterns to identify anomalies

How to Mitigate CVE-2026-24437

Immediate Actions Required

• Clear browser cache on all systems used to administer the Tenda W30E V2 router
• Use private/incognito browsing mode for all router administration tasks until a patch is available
• Restrict physical and remote access to workstations used for router management
• Consider replacing affected devices with alternatives that implement proper security headers
• Implement network segmentation to limit exposure of the router's administrative interface

Patch Information

As of the last update on 2026-01-28, no vendor patch has been released for this vulnerability. Administrators should monitor the Tenda W30E Product Page for firmware updates and review the VulnCheck Advisory for additional guidance.

Workarounds

• Always use private/incognito browser sessions when accessing the router's administrative interface
• Manually clear browser cache and history immediately after completing administrative tasks
• Avoid administering the router from shared or public computers
• Configure browser security settings to minimize cache retention for all sites
• Consider using dedicated administrative workstations with strict access controls

# Browser cache clearing commands for common browsers
# Chrome (Linux)
rm -rf ~/.cache/google-chrome/Default/Cache/*

# Firefox (Linux)
rm -rf ~/.cache/mozilla/firefox/*.default-release/cache2/*

# Clear cache directories after each administrative session
# and consider automating this process for admin workstations