CVE-2026-89173: Smart Video Intercom Information Disclosure

CVE-2026-89173 Overview

CVE-2026-89173 is a sensitive data exposure vulnerability in the Smart Video Intercom System developed by Kingdom Communication Associated. The system returns observably different responses for valid versus invalid user identifiers. Unauthenticated remote attackers can leverage these response differences to enumerate valid user accounts across the network. The weakness is categorized as [CWE-204] Observable Response Discrepancy.

Account enumeration lowers the cost of follow-on attacks such as credential stuffing, password spraying, and targeted phishing against intercom system operators and residents. Because the flaw requires no authentication and can be exercised over the network, automated tooling can iterate large identifier spaces quickly.

Critical Impact
Remote unauthenticated attackers can enumerate valid accounts on affected Smart Video Intercom deployments, enabling downstream credential attacks.

Affected Products

Kingdom Communication Associated Smart Video Intercom System (specific versions not disclosed in the advisory)

Discovery Timeline

2026-09-11 - CVE-2026-89173 published to the National Vulnerability Database (NVD)
2026-09-11 - Last updated in NVD database

Technical Details for CVE-2026-89173

Vulnerability Analysis

The Smart Video Intercom System exposes an authentication or account-lookup interface that returns distinguishable responses depending on whether a submitted identifier corresponds to an existing account. Attackers observe these discrepancies to separate valid identifiers from invalid ones without ever completing authentication.

Typical discrepancies in this class of flaw include different error messages, differing HTTP status codes, response length variations, or measurable timing gaps between the two code paths. Any of these signals can be scraped programmatically to build a list of real accounts.

Account enumeration is a precondition for higher-impact attacks. Once valid accounts are known, adversaries can direct password spraying at those accounts, launch tailored phishing against identified users, or attempt credential replay from prior breach corpora.

Root Cause

The root cause is inconsistent response handling between the valid-account and invalid-account code paths. Secure authentication flows must return generic, indistinguishable responses regardless of whether the supplied identifier exists. The affected system violates this principle, allowing an observer to infer account state.

Attack Vector

The attack is network-based and requires no privileges or user interaction. An attacker submits sequential or dictionary-based identifiers to the exposed endpoint and records the response characteristics. Automation scripts can process thousands of candidate identifiers per minute. See the TWCERT Security Advisory for vendor-coordinated details.

No verified proof-of-concept code has been published. The vulnerability mechanism is described in prose because no code has been released by the reporter or vendor.

Detection Methods for CVE-2026-89173

Indicators of Compromise

High-volume sequential or dictionary-style requests to authentication, login, or account-lookup endpoints originating from a single source or small pool of IP addresses.
Abnormal ratios of failed authentication attempts to unique usernames within short time windows.
Requests that iterate predictable identifier formats such as employee IDs, phone numbers, or email prefixes.

Detection Strategies

Instrument the intercom system's web tier to log all authentication and lookup requests with source IP, submitted identifier, response code, response size, and processing time.
Baseline normal request volume per source and alert on statistical deviations that indicate enumeration behavior.
Correlate authentication endpoint activity with reconnaissance signals such as directory brute forcing or port scans from the same source.

Monitoring Recommendations

Forward web server and application logs from the intercom system to a centralized analytics platform for retention and query.
Build detections for repeated requests that differ only in the username or account field.
Review authentication error distributions weekly to detect slow, low-and-slow enumeration campaigns.

How to Mitigate CVE-2026-89173

Immediate Actions Required

Restrict network exposure of the Smart Video Intercom System management interfaces to trusted administrative networks or VPN segments.
Deploy rate limiting and IP-based throttling on authentication and account-lookup endpoints to slow enumeration attempts.
Enable account lockout or progressive backoff after repeated failed lookups from the same source.
Contact Kingdom Communication Associated and monitor the TWCERT Security Advisory for patch availability.

Patch Information

The advisory published by TWCERT does not list a specific patched version in the referenced disclosure. Operators should engage the vendor directly for a fixed release and apply it as soon as it becomes available. Refer to the TWCERT Incident Report for coordination details.

Workarounds

Place the intercom management interface behind a reverse proxy or web application firewall that normalizes error responses and enforces request rate limits.
Configure the front-end to return uniform generic responses for both valid and invalid identifiers until a vendor patch is available.
Require multi-factor authentication on any downstream systems that share account identifiers with the intercom platform to reduce the value of enumerated accounts.
Segment the intercom system into a dedicated VLAN and restrict inbound access to management ports.

bash

# Example NGINX reverse proxy hardening for the intercom login endpoint
limit_req_zone $binary_remote_addr zone=intercom_auth:10m rate=5r/m;

server {
    listen 443 ssl;
    server_name intercom.example.internal;

    location /login {
        limit_req zone=intercom_auth burst=3 nodelay;
        proxy_pass http://intercom_backend;
        proxy_intercept_errors on;
        error_page 400 401 403 404 = @generic_error;
    }

    location @generic_error {
        return 401 '{"error":"authentication failed"}';
        add_header Content-Type application/json;
    }
}