CVE-2026-50089

Executive Summary

CVE-2026-50089 is an open redirect vulnerability (CWE-601) in the Aqara IAM/SSO Gateway hosted at gw-builder.aqara.com. An unauthenticated attacker can craft a URL that, when clicked by a victim, redirects them to an arbitrary external site. This flaw is rated CVSS 6.1 (Medium) due to the requirement for user interaction and the potential for phishing attacks. The vulnerability remains unpatched as of the latest intelligence, with no official fix or workaround published by Aqara. The EPSS score is 0.0%, indicating low current exploitation activity, but the public nature of the flaw makes it a viable target for social engineering campaigns.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network – The vulnerability is exploitable remotely.
• Attack Complexity (AC): Low – No special conditions required.
• Privileges Required (PR): None – No authentication needed.
• User Interaction (UI): Required – The victim must click a crafted link.
• Scope (SC): Changed – The redirect can lead to a different security domain.
• Confidentiality (C): Low – Limited information disclosure possible via phishing.
• Integrity (I): Low – The redirect can alter the user’s intended destination.
• Availability (A): None – No impact on service availability.

Threat Level: Medium. While the CVSS score is moderate, the open redirect can be weaponized in phishing campaigns to steal credentials or deliver malware, especially given the trusted Aqara domain.

Deep Dive & Mechanics

The Aqara IAM/SSO Gateway at gw-builder.aqara.com handles authentication and session management for Aqara’s ecosystem. The open redirect occurs when the application accepts a user-controlled parameter (likely redirect_uri, returnUrl, or similar) without proper validation. An attacker can craft a URL such as:

https://gw-builder.aqara.com/login?redirect_uri=https://evil.com/phish

When a victim clicks this link, they are first taken to the legitimate Aqara login page, but after authentication (or even without it, depending on the endpoint), the application redirects the browser to the attacker-controlled site. This bypasses URL filters that trust the aqara.com domain and can be used to harvest credentials or install malware.

The vulnerability is a classic instance of CWE-601, where the application fails to sanitize or whitelist redirect destinations. No authentication is required to trigger the redirect, and the attack complexity is low.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code pattern is inferred. A typical vulnerable implementation might look like:

# Vulnerable Python Flask example
@app.route('/login')
def login():
    redirect_url = request.args.get('redirect_uri')
    # No validation of redirect_url
    return redirect(redirect_url)

A patched version would validate the redirect against a whitelist:

# Patched version
ALLOWED_REDIRECTS = ['https://account.aqara.com', 'https://home.aqara.com']

@app.route('/login')
def login():
    redirect_url = request.args.get('redirect_uri')
    if redirect_url in ALLOWED_REDIRECTS:
        return redirect(redirect_url)
    else:
        return redirect('https://account.aqara.com')

Without an official patch, users must rely on external mitigations.

Exploitation & Lab Setup

Red Team

Objective: Demonstrate the open redirect for phishing.

Lab Setup:

1. Set up a controlled environment with a domain you own (e.g., evil.com).
2. Host a phishing page that mimics the Aqara login form.
3. Craft the exploit URL:

https://gw-builder.aqara.com/login?redirect_uri=https://evil.com/phish

4. Send the link to a test victim via email or social media.
5. When the victim clicks, they are redirected to your phishing page after interacting with the legitimate Aqara site.

Proof of Concept (PoC):

# Simple curl test to verify redirect
curl -v "https://gw-builder.aqara.com/login?redirect_uri=https://evil.com"

If the response includes a Location header pointing to evil.com, the vulnerability is confirmed.

Blue Team

Detection:

• Monitor for unusual redirect_uri parameters in logs.
• Block outbound traffic to known malicious domains.
• Use web application firewalls (WAF) to filter redirect parameters.

Mitigation:

• Implement a strict whitelist of allowed redirect destinations.
• Use relative paths instead of full URLs for redirects.
• Add CSRF tokens to redirect parameters.

Indicators of Compromise (IOCs)

• URL Pattern: https://gw-builder.aqara.com/*redirect_uri=*
• Suspicious Domains: Any domain not in Aqara’s whitelist (e.g., evil.com, phish.net)
• Log Entries: HTTP 302 responses from gw-builder.aqara.com with external Location headers.
• Network Traffic: Outbound connections to untrusted domains shortly after a visit to gw-builder.aqara.com.

Detection Engineering

YARA Rule

rule CVE_2026_50089_Open_Redirect {
    meta:
        description = "Detects open redirect attempts targeting Aqara IAM Gateway"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2026-50089"
    strings:
        $redirect_param = /redirect_uri=https?:\/\/[^a]/
        $host = "gw-builder.aqara.com"
    condition:
        $host and $redirect_param
}

Sigma Rule

title: Aqara IAM Gateway Open Redirect Attempt
id: 8f3c2a1b-4d5e-6f7a-8b9c-0d1e2f3a4b5c
status: experimental
description: Detects HTTP requests to gw-builder.aqara.com with suspicious redirect_uri parameters
author: Valters IT
date: 2025/04/10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-host: "gw-builder.aqara.com"
        cs-uri-query|contains: "redirect_uri="
    filter:
        cs-uri-query|contains:
            - "redirect_uri=https://account.aqara.com"
            - "redirect_uri=https://home.aqara.com"
    condition: selection and not filter
falsepositives:
    - Legitimate redirects to whitelisted domains
level: medium

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2026-50089 Aqara IAM Gateway Open Redirect";
    flow:to_server,established;
    content:"gw-builder.aqara.com"; http_host;
    content:"redirect_uri="; http_uri;
    pcre:"/redirect_uri=https?:\/\/[^a]/";
    sid:1000001;
    rev:1;
    priority:2;
)

Remediation & Mitigation

1. Vendor Action: Aqara must implement a whitelist of allowed redirect destinations and validate all redirect parameters server-side.
2. User Awareness: Educate users not to click on suspicious links, even if they appear to come from Aqara.
3. WAF Rules: Deploy WAF rules to block requests with redirect_uri pointing to external domains not in the whitelist.
4. Monitoring: Enable logging and alerting for unusual redirect patterns.
5. Temporary Workaround: If possible, disable the redirect functionality or use a reverse proxy to filter requests.

Valters IT
DevSecOps & Cyber Threat Intelligence