CVE-2026-3926: Google Chrome Buffer Overflow Vulnerability

CVE-2026-3926 Overview

CVE-2026-3926 is an out-of-bounds read vulnerability in the V8 JavaScript engine used by Google Chrome. The flaw affects Chrome versions prior to 146.0.7680.71 on Windows, macOS, and Linux. A remote attacker can trigger out-of-bounds memory access by serving a crafted HTML page to a target user. Successful exploitation requires user interaction, typically visiting an attacker-controlled site. The issue is tracked under [CWE-125: Out-of-bounds Read] and was addressed in the Chrome Stable channel update released by Google in March 2026.

Critical Impact

A remote attacker can read out-of-bounds memory in the V8 engine through a crafted HTML page, potentially exposing sensitive process memory and enabling further exploitation chains.

Affected Products

• Google Chrome prior to 146.0.7680.71 on Microsoft Windows
• Google Chrome prior to 146.0.7680.71 on Apple macOS
• Google Chrome prior to 146.0.7680.71 on Linux

Discovery Timeline

• 2026-03-11 - CVE-2026-3926 published to NVD
• 2026-03-13 - Last updated in NVD database

Technical Details for CVE-2026-3926

Vulnerability Analysis

The vulnerability resides in V8, the JavaScript and WebAssembly engine that powers Chrome. V8 performs just-in-time (JIT) compilation and manages complex memory structures for JavaScript objects. An out-of-bounds read occurs when the engine accesses memory outside the bounds of an allocated buffer or object during script execution.

The flaw allows a remote attacker to read memory contents beyond intended boundaries when V8 processes attacker-controlled JavaScript on a crafted HTML page. Disclosed memory may include pointers, object metadata, or other process data useful for bypassing Address Space Layout Randomization (ASLR) or chaining with other memory corruption bugs.

Chromium classified the underlying severity as Medium, while the NVD score reflects broader impact when combined with renderer-process exposure.

Root Cause

The root cause is improper bounds validation within V8 when handling specific JavaScript operations. Such defects in V8 typically stem from optimizer assumptions that no longer hold during runtime, leading the engine to compute offsets that exceed allocated buffer lengths. Google has not published the precise code path; details remain restricted in the Chromium Issue Tracker Report until a majority of users have updated.

Attack Vector

Exploitation requires the victim to load a crafted HTML page in a vulnerable Chrome build. The attacker hosts JavaScript that triggers the vulnerable code path inside V8. No authentication or elevated privileges are required, but user interaction is necessary. The attack can be delivered through phishing, malvertising, watering-hole compromises, or any web content the user is enticed to visit.

No verified public exploit or proof-of-concept code is available for CVE-2026-3926 at the time of publication. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.

Detection Methods for CVE-2026-3926

Indicators of Compromise

• Chrome renderer process crashes referencing V8 stack traces after visiting untrusted web pages
• Unexpected child process spawns from chrome.exe or the macOS/Linux Chrome helper processes
• Outbound connections to newly registered domains shortly after browser navigation events
• Browser telemetry indicating versions of Chrome below 146.0.7680.71 still deployed in the environment

Detection Strategies

• Inventory installed Chrome versions across endpoints and flag hosts running builds prior to 146.0.7680.71
• Monitor for anomalous memory access violations and crash dumps generated by Chrome renderer processes
• Inspect HTTP proxy and DNS logs for users visiting suspicious sites delivering heavily obfuscated JavaScript

Monitoring Recommendations

• Enable enterprise browser telemetry through Chrome Browser Cloud Management to track version compliance
• Forward endpoint process and network telemetry to a centralized analytics platform for correlation across browser, process, and network events
• Alert on post-exploitation behaviors such as renderer processes writing to disk, loading unsigned modules, or initiating reverse shells

How to Mitigate CVE-2026-3926

Immediate Actions Required

• Update Google Chrome to version 146.0.7680.71 or later on all Windows, macOS, and Linux endpoints
• Restart Chrome on user systems to ensure the patched binary is loaded into memory
• Audit Chromium-based applications and embedded browser components that may bundle vulnerable V8 builds
• Communicate the update requirement to users and enforce compliance through endpoint management tooling

Patch Information

Google released the fix in the Chrome Stable channel update documented in the Google Chrome Update Announcement. Administrators should deploy version 146.0.7680.71 or later. Chromium-based browsers such as Microsoft Edge, Brave, Opera, and Vivaldi typically issue corresponding updates and should be patched once vendor releases are available.

Workarounds

• Restrict JavaScript execution on untrusted sites using Chrome enterprise policies until patching is complete
• Deploy network-level controls that block access to known malicious or newly registered domains
• Enable Site Isolation and Enhanced Safe Browsing in Chrome to reduce the blast radius of renderer compromise
• Use application allowlisting to prevent unauthorized child processes from launching following browser exploitation

# Verify the installed Chrome version on Linux
google-chrome --version

# Force update via command line on macOS
/Library/Google/GoogleSoftwareUpdate/GoogleSoftwareUpdate.bundle/Contents/Resources/GoogleSoftwareUpdateAgent.app/Contents/MacOS/GoogleSoftwareUpdateAgent -runMode oneshot -userInitiated YES

# Windows: query installed Chrome version from the registry
reg query "HKLM\Software\Google\Update\Clients\{8A69D345-D564-463C-AFF1-A69D9E530F96}" /v pv