CVE-2025-49464: Zoom Client Buffer Overflow Vulnerability

CVE-2025-49464 Overview

A classic buffer overflow vulnerability has been identified in certain Zoom Clients for Windows. This memory corruption flaw may allow an authenticated user to conduct a denial of service attack via network access. The vulnerability is classified as CWE-120 (Buffer Copy without Checking Size of Input), indicating improper bounds checking during memory operations.

Critical Impact

Authenticated attackers can exploit this buffer overflow vulnerability over the network to cause denial of service conditions, potentially disrupting business communications for organizations relying on Zoom for Windows.

Affected Products

• Zoom Client for Windows (all vulnerable versions)
• Zoom Zoom application for Windows platform

Discovery Timeline

• July 10, 2025 - CVE-2025-49464 published to NVD
• August 5, 2025 - Last updated in NVD database

Technical Details for CVE-2025-49464

Vulnerability Analysis

This classic buffer overflow vulnerability (CWE-120) affects the Zoom Client for Windows. The flaw occurs when the application copies data to a buffer without properly verifying that the input size does not exceed the buffer's allocated capacity. When exploited, this leads to memory corruption that can destabilize the application and cause it to crash.

The vulnerability requires network access for exploitation, meaning an attacker must be able to send crafted data to the vulnerable Zoom client over the network. Importantly, the attacker must have low-level privileges (authenticated user status) to successfully trigger the vulnerability. While this limits the attack surface compared to unauthenticated vulnerabilities, it remains a significant concern in enterprise environments where authenticated users may be malicious insiders or compromised accounts.

The primary impact is availability disruption—attackers can cause the Zoom client to crash or become unresponsive, interrupting video conferences and communications. The vulnerability does not appear to allow data exfiltration or modification, as the impact is limited to denial of service.

Root Cause

The root cause is a classic buffer overflow condition (CWE-120: Buffer Copy without Checking Size of Input). The vulnerable code path copies data into a fixed-size buffer without adequately validating the length of the input data. When input exceeds the expected size, it overwrites adjacent memory, corrupting data structures critical to application stability.

This type of vulnerability typically occurs when developers use unsafe memory copy functions or fail to implement proper bounds checking on user-supplied input before processing.

Attack Vector

The attack vector is network-based, requiring the attacker to send specially crafted data to the Zoom client. The attacker must have authenticated access (low privilege level required) to exploit this vulnerability. The attack does not require user interaction, meaning once the malicious payload is delivered over the network, the buffer overflow is triggered automatically.

An attacker would need to craft input data that exceeds expected buffer boundaries, causing the overflow condition. The exploitation results in denial of service by corrupting critical memory regions, leading to application instability or crashes.

For detailed technical information about this vulnerability, refer to the Zoom Security Bulletin ZSB-25028.

Detection Methods for CVE-2025-49464

Indicators of Compromise

• Unexpected Zoom client crashes during active meetings or when processing network data
• Application crash logs showing memory access violations or buffer overflow signatures
• Repeated Zoom client restarts without user initiation
• Windows Error Reporting events indicating Zoom process failures with memory corruption indicators

Detection Strategies

• Monitor Windows Event Logs for Zoom client crash events and application faults
• Deploy endpoint detection rules to identify abnormal memory access patterns in Zoom processes
• Implement network monitoring to detect anomalous traffic patterns targeting Zoom client ports
• Configure application crash monitoring to alert on repeated Zoom client failures

Monitoring Recommendations

• Enable verbose logging on Zoom clients where supported to capture pre-crash activity
• Monitor for unusual network traffic directed at Zoom client endpoints
• Implement centralized crash reporting to identify patterns across multiple endpoints
• Deploy SentinelOne agents to detect exploitation attempts through behavioral analysis of the Zoom process

How to Mitigate CVE-2025-49464

Immediate Actions Required

• Review the Zoom Security Bulletin ZSB-25028 for specific affected versions and remediation guidance
• Update Zoom Client for Windows to the latest patched version as specified in the vendor advisory
• Inventory all systems running Zoom Client for Windows and prioritize patching for internet-facing or high-value targets
• Ensure endpoint protection solutions are updated to detect exploitation attempts

Patch Information

Zoom has released security updates to address this vulnerability. Organizations should consult the Zoom Security Bulletin ZSB-25028 for specific version information and download links. Apply the latest Zoom Client for Windows update to remediate this vulnerability.

Workarounds

• Restrict network access to Zoom clients using firewall rules to limit exposure to trusted networks only
• Implement network segmentation to isolate systems running vulnerable Zoom versions
• Monitor Zoom client processes for abnormal behavior using endpoint detection and response tools
• Consider temporarily restricting Zoom usage on critical systems until patches can be applied