CVE-2026-108184: Zoom Client Certificate Validation Flaw

CVE-2026-108184 Overview

CVE-2026-108184 is an improper certificate validation vulnerability [CWE-295] affecting certain Zoom Clients for Windows. The flaw allows an unauthenticated remote attacker with network access to conduct information disclosure. Because the client fails to properly validate the server certificate, an attacker positioned to intercept network traffic can present a fraudulent certificate and read data intended to remain confidential within a Transport Layer Security (TLS) session.

Critical Impact
An unauthenticated attacker with network-adjacent access can intercept Zoom client traffic and extract confidential session data by exploiting broken certificate validation.

Affected Products

Zoom Clients for Windows (specific versions listed in Zoom Security Bulletin ZSB-26021)
Zoom Workplace App for Windows (per vendor advisory)
Related Zoom Windows desktop components as enumerated by the vendor

Discovery Timeline

2026-10-13 - CVE-2026-108184 published to the National Vulnerability Database (NVD)
2026-10-15 - Last updated in NVD database
2026-10-15 - EPSS score published at 0.158%

Technical Details for CVE-2026-108184

Vulnerability Analysis

The vulnerability is categorized under Improper Certificate Validation [CWE-295]. Zoom Clients for Windows do not correctly verify the authenticity of the X.509 certificate presented by a remote endpoint during the TLS handshake. When validation is incomplete, the client cannot reliably distinguish a legitimate server from an impostor. An attacker who intercepts or redirects client traffic can therefore establish a trusted session using a certificate the client should have rejected. The result is a man-in-the-middle condition that exposes session content to an unauthenticated adversary.

Successful exploitation requires network-adjacent positioning, which raises attack complexity. However, no authentication or user interaction is required. The confidentiality and integrity of transmitted data are both at risk, while availability is not impacted.

Root Cause

The root cause is the client's failure to enforce one or more required certificate validation checks. These checks typically include signature verification against a trusted certificate authority, hostname matching against the Subject or Subject Alternative Name, validity period enforcement, and revocation status. Skipping or weakening any of these steps allows a crafted certificate to be accepted as valid.

Attack Vector

The attack vector is network-based. An adversary with the ability to intercept traffic between a Zoom Windows client and Zoom infrastructure, such as through a compromised Wi-Fi network, rogue access point, Address Resolution Protocol (ARP) spoofing, or Border Gateway Protocol (BGP) hijacking, can present a fraudulent server certificate. If the client accepts the certificate without proper validation, the attacker decrypts the TLS tunnel and reads information passed through it. No code execution against the client is required to disclose data.

No verified public exploit code is available for CVE-2026-108184. See the Zoom Security Bulletin ZSB-26021 for vendor technical details.

Detection Methods for CVE-2026-108184

Indicators of Compromise

Unexpected TLS certificates presented to Zoom clients that do not chain to a Zoom-trusted certificate authority
TLS sessions from Zoom client processes terminating at IP addresses outside Zoom's published infrastructure ranges
Anomalous ARP or Dynamic Host Configuration Protocol (DHCP) activity on networks where Zoom clients operate

Detection Strategies

Inspect endpoint network telemetry for Zoom client connections and compare presented certificate fingerprints against expected Zoom certificate authorities
Correlate process-level network activity from Zoom.exe and related binaries with destination reputation and ASN data
Alert on certificate chain anomalies, self-signed certificates, or certificates with mismatched Subject Alternative Names observed in Zoom traffic flows

Monitoring Recommendations

Enable TLS inspection on egress proxies to flag Zoom traffic terminating at non-Zoom endpoints
Monitor for outdated Zoom client versions across the Windows estate using software inventory tooling
Collect and retain DNS query logs for Zoom-related hostnames to identify redirection or hijack attempts

How to Mitigate CVE-2026-108184

Immediate Actions Required

Update all Zoom Clients for Windows to the fixed version identified in Zoom Security Bulletin ZSB-26021
Enforce automatic updates for the Zoom client across managed Windows endpoints
Audit endpoints for outdated Zoom installations and prioritize remediation on devices used on untrusted networks

Patch Information

Zoom has published fixed versions in Zoom Security Bulletin ZSB-26021. Administrators should consult the bulletin for the exact affected and fixed version ranges and deploy the corresponding update through standard software distribution channels.

Workarounds

Restrict Zoom client usage on untrusted networks until patching is complete
Require corporate virtual private network (VPN) connectivity for remote users running Zoom to reduce exposure to adversary-controlled networks
Enforce HTTP Strict Transport Security (HSTS) and certificate pinning at the network perimeter where feasible to detect anomalous Zoom certificate presentations

bash

# Verify installed Zoom client version on Windows endpoints
Get-ItemProperty "HKLM:\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\*" | 
  Where-Object { $_.DisplayName -like "*Zoom*" } | 
  Select-Object DisplayName, DisplayVersion, Publisher