CVE-2025-29834: Microsoft Edge Chromium RCE Vulnerability

CVE-2025-29834 Overview

CVE-2025-29834 is an out-of-bounds read vulnerability in Microsoft Edge (Chromium-based) that allows an unauthorized attacker to execute arbitrary code over a network. This memory corruption flaw occurs when the browser reads data beyond the intended memory boundaries, potentially exposing sensitive information or enabling code execution when a user visits a maliciously crafted webpage.

Critical Impact

This vulnerability enables remote code execution through network-based attacks, requiring only user interaction to visit a malicious webpage. Successful exploitation could allow attackers to execute arbitrary code with the privileges of the current user.

Affected Products

• Microsoft Edge (Chromium-based)

Discovery Timeline

• 2025-04-12 - CVE-2025-29834 published to NVD
• 2025-07-08 - Last updated in NVD database

Technical Details for CVE-2025-29834

Vulnerability Analysis

This out-of-bounds read vulnerability (CWE-125) affects Microsoft Edge's Chromium-based browser engine. The flaw allows memory to be read beyond its allocated boundaries, which can lead to information disclosure or, in certain conditions, enable arbitrary code execution. The attack requires network access and user interaction—specifically, the victim must navigate to a malicious website or interact with attacker-controlled content.

The vulnerability requires high attack complexity, meaning specific conditions must be met for successful exploitation. However, no privileges are required by the attacker, making it accessible to unauthenticated threat actors. When exploited, the vulnerability can compromise the confidentiality, integrity, and availability of the affected system.

Root Cause

The root cause of CVE-2025-29834 is improper bounds checking when reading memory in Microsoft Edge's Chromium-based rendering engine. When processing certain types of content, the browser fails to properly validate memory boundaries before read operations, allowing access to memory locations outside the intended buffer. This type of memory safety issue is classified under CWE-125 (Out-of-bounds Read).

Attack Vector

The attack vector for this vulnerability is network-based, requiring user interaction. An attacker would typically:

1. Host malicious content on a website or inject it into a compromised legitimate site
2. Lure the victim to visit the malicious page through phishing or social engineering
3. The malicious content triggers the out-of-bounds read condition in the Edge browser
4. Memory is read beyond intended boundaries, potentially leaking sensitive information
5. Under specific conditions, this memory corruption could be leveraged to achieve arbitrary code execution

The vulnerability does not require authentication or elevated privileges, making it accessible to any attacker who can deliver malicious content to a target user's browser.

Detection Methods for CVE-2025-29834

Indicators of Compromise

• Unusual browser crashes or memory access violations in Microsoft Edge processes
• Anomalous network traffic to suspicious domains immediately before browser instability
• Process injection attempts or unexpected child processes spawned from msedge.exe
• Memory dump artifacts showing out-of-bounds read patterns in browser memory regions

Detection Strategies

• Monitor for unusual behavior patterns in Microsoft Edge processes, including unexpected crashes or high memory consumption
• Deploy endpoint detection rules to identify suspicious process spawning from browser contexts
• Implement network monitoring to detect connections to known malicious domains or infrastructure
• Enable crash reporting and analyze browser crash dumps for exploitation signatures

Monitoring Recommendations

• Enable Windows Event Logging for application crashes and monitor Edge-related events
• Deploy browser telemetry monitoring to track abnormal page loads and script execution patterns
• Implement network segmentation and monitor egress traffic from endpoints running vulnerable Edge versions
• Use SentinelOne's behavioral AI to detect post-exploitation activities following browser compromise

How to Mitigate CVE-2025-29834

Immediate Actions Required

• Update Microsoft Edge to the latest patched version immediately through Windows Update or Microsoft Edge's built-in update mechanism
• Enable automatic browser updates to ensure timely patching of future vulnerabilities
• Restrict access to untrusted websites through web filtering or proxy solutions
• Consider deploying browser isolation technologies for high-risk browsing scenarios

Patch Information

Microsoft has released security updates to address this vulnerability. Refer to the Microsoft Security Response Center advisory for detailed patch information and affected version details. Organizations should prioritize deploying these updates to all systems running Microsoft Edge (Chromium-based).

To update Microsoft Edge:

1. Open Microsoft Edge
2. Navigate to Settings → About Microsoft Edge
3. The browser will automatically check for and install available updates
4. Restart the browser to complete the update process

Workarounds

• Use an alternative browser temporarily until patches can be applied to Microsoft Edge
• Implement web content filtering to block access to untrusted or potentially malicious websites
• Enable Microsoft Defender SmartScreen to provide additional protection against malicious sites
• Consider using browser sandboxing or isolation technologies to contain potential exploitation attempts

# Verify Microsoft Edge version via command line
# Run in PowerShell to check installed Edge version
Get-AppxPackage -Name Microsoft.MicrosoftEdge.Stable | Select-Object Version

# Alternative: Check Edge version via registry
reg query "HKEY_CURRENT_USER\Software\Microsoft\Edge\BLBeacon" /v version