CVE-2026-53410: 
Zoom Client vulnerability analysis and mitigation

CVE-2026-53410 is a Time-of-Check to Time-of-Use (TOCTOU) race condition vulnerability in the installation and uninstallation process of certain Zoom Clients for Windows that could allow an authenticated local user to escalate privileges. It was published by Zoom on July 14, 2026, and added to the NVD and GitHub Advisory Database on July 16, 2026. The vulnerability carries a CVSS v3.1 base score of 7.0 (High) (Zoom Advisory, GitHub Advisory).

The vulnerability is classified as CWE-367 (Time-of-Check Time-of-Use Race Condition), where the Zoom Client installer/uninstaller checks the state of a resource and then uses it, but the resource's state can be altered between the check and the use — a window an attacker can exploit. This is consistent with CAPEC-27 (Leveraging Race Conditions via Symbolic Links) and CAPEC-29 (Leveraging TOCTOU Race Conditions), suggesting the attack may involve manipulating file system objects such as symbolic links during the installation or uninstallation window (Zoom Advisory, GitHub Advisory). Exploitation requires local authenticated access and high attack complexity, as the attacker must win a precise timing race during the install/uninstall process (GitHub Advisory).

Successful exploitation allows an authenticated local user to escalate privileges on the affected Windows system, potentially gaining elevated or SYSTEM-level access. The NVD SSVC assessment rates the technical impact as "total," meaning confidentiality, integrity, and availability are all fully compromised upon successful exploitation. This could enable an attacker to install malware, access sensitive data, or persist on the system with elevated rights, though lateral movement would require additional steps beyond the initial privilege escalation (Zoom Advisory, GitHub Advisory).

There is no public proof-of-concept exploit and no evidence of active in-the-wild exploitation as of the time of disclosure (Zoom Advisory). The NVD SSVC assessment confirms exploitation status as "none" and the vulnerability is not automatable, reflecting the high attack complexity required to win the race condition. The EPSS score is approximately 0.094%, placing it in the 1st percentile for exploitation likelihood within 30 days (GitHub Advisory). The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

1. Gain local access: Obtain an authenticated low-privileged user account on a Windows system running a vulnerable Zoom Client version.
2. Trigger installation or uninstallation: Initiate a Zoom Client installation or uninstallation process, which runs with elevated privileges.
3. Monitor the file system race window: Use tools such as Process Monitor (Procmon) to identify the specific file system resource (e.g., a directory or file) that the installer checks before use.
4. Exploit the race condition: During the brief window between the installer's check and its use of the resource, replace or redirect the target resource — for example, by substituting a symbolic link pointing to a privileged location (consistent with CAPEC-27).
5. Achieve privilege escalation: The elevated installer process follows the attacker-controlled link or uses the manipulated resource, writing attacker-controlled content to a privileged location or executing attacker-controlled code with elevated privileges (Zoom Advisory, GitHub Advisory).

• File System: Unexpected symbolic links created in Zoom installation or temporary directories during install/uninstall operations; files written to privileged system directories (e.g., C:\Windows\System32) by the Zoom installer process.
• Process: Zoom installer or uninstaller process (ZoomInstaller.exe or similar) spawning unexpected child processes or writing to locations outside the expected installation path.
• Logs: Windows Event Logs (Security) showing privilege use or object access events tied to the Zoom installer process at unusual times; audit logs recording file or directory permission changes during Zoom install/uninstall.
• Registry: Unexpected registry key modifications under HKLM\SOFTWARE or HKLM\SYSTEM made by the Zoom installer process outside of normal installation paths.

Zoom has released a patch addressing this vulnerability; users should update to the latest Zoom Client version available at https://zoom.us/download (Zoom Advisory). As a workaround, organizations should restrict installation and uninstallation operations to minimize the timing window for race condition exploitation, and limit who can perform Zoom installs on endpoints. Applying the patch is the recommended and definitive remediation.

The vulnerability received notable media coverage, with outlets including BleepingComputer, The Hacker News, Security Affairs, TechRadar, Heise, and eSecurity Planet reporting on the broader Zoom security bulletin that included this CVE alongside the more critical CVE-2026-53412 (a critical account takeover flaw) (BleepingComputer, The Hacker News, Security Affairs). Much of the community attention was focused on the more severe CVE-2026-53412, with CVE-2026-53410 receiving secondary coverage as part of the same patch batch. The University of Toronto issued an advisory urging users to update their Zoom clients promptly (U of T Advisory).