CVE-2025-49456: Zoom SDK Race Condition Vulnerability

CVE-2025-49456 Overview

CVE-2025-49456 is a race condition vulnerability in the installer for certain Zoom Clients for Windows. The flaw allows an unauthenticated local user to impact application integrity through local access. Zoom disclosed the issue in Security Bulletin ZSB-25029 on August 12, 2025.

The vulnerability is tracked under two Common Weakness Enumeration (CWE) categories: [CWE-362] (concurrent execution using shared resource with improper synchronization) and [CWE-426] (untrusted search path). The affected products span the full Windows client portfolio, including Zoom Workplace Desktop, Zoom Rooms, and the Meeting SDK.

Critical Impact
A successful race condition exploit can compromise the integrity of the installed Zoom application, potentially enabling attackers to substitute or modify installer-loaded components during a narrow execution window.

Affected Products

Zoom Meeting Software Development Kit for Windows
Zoom Workplace Desktop for Windows
Zoom Workplace Virtual Desktop Infrastructure (VDI) for Windows
Zoom Rooms and Zoom Rooms Controller for Windows

Discovery Timeline

2025-08-12 - CVE-2025-49456 published to NVD and disclosed in Zoom Security Bulletin ZSB-25029
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-49456

Vulnerability Analysis

The vulnerability resides in the Windows installer component shared across multiple Zoom client products. During installation or update operations, the installer performs sequential checks and file operations that are not properly synchronized. A local unauthenticated user with access to the system can interfere with the installer between the time it validates a resource and the time it uses that resource.

The flaw combines two weakness classes. The race condition ([CWE-362]) creates the exploitable timing window. The untrusted search path issue ([CWE-426]) means the installer may load or reference components from locations a local user can influence. Together, these weaknesses allow attackers to affect what the installer ultimately writes or executes.

The attack impact is limited to application integrity. Confidentiality and availability are not directly affected. However, integrity compromise of an installed communication client creates downstream risk, since modified binaries may persist and execute with the privileges of subsequent Zoom sessions.

Root Cause

The root cause is improper synchronization in the installer workflow combined with reliance on file paths or search locations that a non-privileged local user can manipulate. The installer does not adequately lock or verify resources between validation and use, creating a time-of-check to time-of-use (TOCTOU) condition.

Attack Vector

Exploitation requires local access to the Windows host during an installer or update execution. The attack complexity is high because the attacker must win a narrow timing race and stage manipulated files or paths before the installer consumes them. No user interaction and no prior authentication are required beyond local presence.

No verified exploit code is publicly available. See Zoom Security Bulletin ZSB-25029 for vendor-provided technical context.

Detection Methods for CVE-2025-49456

Indicators of Compromise

Unexpected files or DLLs appearing in Zoom installer working directories or temporary paths during installation or update.
Modified Zoom binaries in %ProgramFiles%\Zoom or %AppData%\Zoom that do not match vendor-signed hashes.
Non-privileged processes creating or modifying files in installer staging directories concurrent with ZoomInstaller.exe execution.

Detection Strategies

Monitor for concurrent file write operations by non-installer processes during Zoom installation or update events.
Validate digital signatures on all Zoom binaries after installation completes and flag any unsigned or mismatched components.
Correlate installer execution events with file system activity in world-writable or user-writable paths referenced by the installer.

Monitoring Recommendations

Enable Windows Sysmon Event ID 11 (FileCreate) monitoring on Zoom installation directories and installer temp paths.
Track process creation events where ZoomInstaller.exe or related MSI processes execute alongside unrelated user-context processes touching the same paths.
Review endpoint telemetry for anomalous DLL loads by Zoom client processes after an install or update cycle.

How to Mitigate CVE-2025-49456

Immediate Actions Required

Update all Zoom Windows clients to the fixed versions identified in Zoom Security Bulletin ZSB-25029.
Restrict interactive local access on systems running Zoom clients to trusted users only.
Deploy Zoom updates through managed software distribution channels rather than allowing user-initiated installs where feasible.

Patch Information

Zoom addressed CVE-2025-49456 in the client versions listed in Security Bulletin ZSB-25029, published August 12, 2025. Administrators should consult the bulletin for the exact fixed build numbers per product line, including Zoom Workplace Desktop, Zoom Workplace VDI, Zoom Rooms, Zoom Rooms Controller, and the Zoom Meeting SDK for Windows.

Workarounds

Perform Zoom installations and updates only from administrator accounts on hosts with no concurrent interactive user sessions.
Enforce application allowlisting to prevent execution of unsigned binaries in Zoom installation directories.
Restrict write permissions on installer staging paths where feasible to reduce the attacker's ability to plant race-condition payloads.

bash

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

# Validate digital signatures on Zoom binaries after install
Get-ChildItem "C:\Program Files\Zoom\bin\*.exe","C:\Program Files\Zoom\bin\*.dll" |
  ForEach-Object { Get-AuthenticodeSignature $_.FullName } |
  Where-Object { $_.Status -ne "Valid" }