CVE-2024-43595: Microsoft Edge Chromium RCE Vulnerability

CVE-2024-43595 Overview

CVE-2024-43595 is a remote code execution vulnerability affecting Microsoft Edge (Chromium-based). The flaw is associated with CWE-126: Buffer Over-read, which can lead to memory corruption when the browser processes attacker-controlled content. Successful exploitation requires user interaction, typically by visiting a crafted web page. An attacker who exploits this flaw can execute arbitrary code in the context of the current user, leading to compromise of confidentiality, integrity, and availability on the affected host. Microsoft published the advisory through the Microsoft Security Update Guide.

Critical Impact

Remote attackers can achieve code execution on Microsoft Edge users by luring them to malicious web content, gaining the privileges of the logged-in user.

Affected Products

• Microsoft Edge (Chromium-based)
• cpe:2.3:a:microsoft:edge_chromium:*:*:*:*:*:*:*:*
• Browser instances running versions prior to the October 2024 security update

Discovery Timeline

• 2024-10-17 - CVE-2024-43595 published to NVD
• 2024-10-18 - Last updated in NVD database

Technical Details for CVE-2024-43595

Vulnerability Analysis

The vulnerability resides in Microsoft Edge (Chromium-based) and is categorized under CWE-126: Buffer Over-read. A buffer over-read occurs when the browser reads memory beyond the bounds of an allocated buffer while parsing or processing untrusted input. In a browser context, such conditions can expose adjacent memory, destabilize the renderer process, or be chained with additional primitives to achieve code execution. Microsoft classifies CVE-2024-43595 as a remote code execution flaw, indicating that the over-read condition is reachable through web-delivered content and can be leveraged to run attacker-supplied code under the user's privileges.

Root Cause

The root cause is improper boundary handling during the processing of attacker-controlled data inside the Chromium-based Edge engine. When the affected code path reads past the end of an allocated buffer, it accesses memory that may contain sensitive runtime values or pointers. An attacker who controls the layout of nearby objects can shape memory to convert the over-read into a usable exploitation primitive.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker hosts a crafted web page or delivers malicious content through advertising networks, links in email, or compromised sites. When the user visits the page in a vulnerable version of Edge, the browser parses the content and triggers the over-read. The EPSS score is 0.619% with a percentile of 70.353, reflecting moderate exploitation likelihood relative to other published CVEs. No public proof-of-concept or in-the-wild exploitation has been reported.

No verified proof-of-concept code is available. Refer to the Microsoft Security Update Guide for vendor-provided technical context.

Detection Methods for CVE-2024-43595

Indicators of Compromise

• Unexpected child processes spawned by msedge.exe, such as command interpreters or scripting hosts
• Edge renderer crashes or repeated WerFault.exe events correlated with browsing activity
• Outbound connections from msedge.exe to newly registered or low-reputation domains
• Creation of executables or scripts in user-writable paths shortly after a browsing session

Detection Strategies

• Monitor endpoint telemetry for anomalous process trees originating from msedge.exe and its child renderer processes
• Inspect web proxy and DNS logs for users visiting domains hosting exploit kits or malvertising infrastructure
• Apply behavioral analytics to detect post-exploitation activity such as credential access, persistence, or lateral movement following browser execution
• Cross-reference Edge version inventory from configuration management against the patched build numbers published by Microsoft

Monitoring Recommendations

• Track Edge version compliance across the fleet and alert on hosts running unpatched builds
• Enable script block logging and command-line auditing on Windows endpoints to capture post-exploitation activity
• Forward browser and EDR telemetry to a centralized data lake for correlation with threat intelligence feeds
• Alert on Edge processes writing to autostart locations, scheduled tasks, or registry run keys

How to Mitigate CVE-2024-43595

Immediate Actions Required

• Update Microsoft Edge (Chromium-based) to the latest stable channel release published on or after October 17, 2024
• Verify automatic update settings are enabled across managed endpoints to prevent version drift
• Audit endpoints for unpatched Edge installations and prioritize remediation on internet-facing user workstations
• Communicate user awareness guidance about avoiding untrusted links and attachments until patches are deployed

Patch Information

Microsoft has released a security update addressing CVE-2024-43595. Apply the fix referenced in the Microsoft Security Update Guide. Edge updates are delivered through the standard browser update mechanism and through Microsoft Update for managed environments.

Workarounds

• Restrict use of Microsoft Edge for browsing untrusted external sites until patching is complete
• Deploy web filtering and DNS security controls to block known malicious and newly registered domains
• Enforce least-privilege user accounts so that browser-delivered code cannot escalate to administrative actions
• Disable or restrict browser features that process untrusted active content where business needs allow

# Verify the installed Edge version on Windows endpoints
reg query "HKLM\SOFTWARE\Microsoft\Edge\BLBeacon" /v version

# Force Edge to check for updates via the management policy directory
"%ProgramFiles(x86)%\Microsoft\EdgeUpdate\MicrosoftEdgeUpdate.exe" /ua /installsource scheduler