CVE-2026-6317: Google Chrome Use-After-Free Vulnerability

CVE-2026-6317 Overview

CVE-2026-6317 is a use-after-free vulnerability in the Cast component of Google Chrome versions prior to 147.0.7727.101. A remote attacker can exploit this flaw by serving a crafted HTML page to a victim, triggering memory corruption that leads to arbitrary code execution in the renderer process. Google's Chromium security team rated the issue as High severity. The flaw is tracked under CWE-416: Use After Free and affects Chrome on Windows, macOS, and Linux. Successful exploitation requires user interaction, typically visiting an attacker-controlled web page. Google addressed the vulnerability in the Stable channel update released on April 15, 2026.

Critical Impact

Remote attackers can execute arbitrary code on a victim's machine by luring them to a crafted web page that exploits dangling memory references in Chrome's Cast feature.

Affected Products

• Google Chrome prior to 147.0.7727.101 on Microsoft Windows
• Google Chrome prior to 147.0.7727.101 on Apple macOS
• Google Chrome prior to 147.0.7727.101 on Linux

Discovery Timeline

• 2026-04-15 - Google releases Stable channel update fixing the issue
• 2026-04-15 - CVE-2026-6317 published to NVD
• 2026-04-17 - Last updated in NVD database

Technical Details for CVE-2026-6317

Vulnerability Analysis

The vulnerability resides in Chrome's Cast component, which handles media casting to remote display devices such as Chromecast. A use-after-free condition occurs when the Cast subsystem retains a pointer to an object that has already been deallocated. When the dangling pointer is dereferenced, attacker-controlled data can occupy the freed memory region. This lets attackers manipulate object state, corrupt vtables, and ultimately hijack control flow within the rendering process. Exploitation typically pairs the primitive with a sandbox escape to achieve full system compromise.

Root Cause

The defect is classified as [CWE-416: Use After Free]. The Cast module fails to invalidate references to objects after their lifetime ends, leaving stale pointers reachable from JavaScript-driven code paths. Crafted HTML and JavaScript that exercise specific Cast APIs can free an internal object while another code path still holds and uses the pointer. Use-after-free defects in browser components are a recurring source of remote code execution because attackers can groom the heap to control reallocation.

Attack Vector

An attacker hosts a malicious HTML page that scripts the Cast API in a sequence designed to trigger the freed-object access. When a Chrome user visits the page, the renderer executes the script, the use-after-free fires, and the attacker gains arbitrary code execution within the sandboxed renderer process. User interaction is limited to visiting the page or clicking a link. No authentication is required, and the attack proceeds entirely over the network. Refer to the Chromium Issue Tracker Entry for further technical context once Google unrestricts the bug.

Detection Methods for CVE-2026-6317

Indicators of Compromise

• Chrome renderer process crashes or unexpected exits referencing cast or media_router modules in crash logs.
• Outbound connections from Chrome to unknown casting endpoints immediately following navigation to untrusted sites.
• Child processes spawned by chrome.exe (Windows), Google Chrome Helper (macOS), or chrome (Linux) that do not match normal browser behavior.

Detection Strategies

• Inventory installed Chrome versions across the fleet and flag any instance below 147.0.7727.101.
• Monitor endpoint telemetry for renderer-to-shell process lineage originating from Chrome, a common post-exploitation pattern after browser memory corruption.
• Correlate web proxy logs with crash telemetry to identify users who visited suspicious pages immediately before a Chrome crash.

Monitoring Recommendations

• Enable Chrome crash reporting and forward Crashpad dumps to a centralized log platform for analyst review.
• Alert on process injection or unsigned module loads inside Chrome processes.
• Track Chrome update compliance through endpoint management tooling and report on devices that have not received the patched build.

How to Mitigate CVE-2026-6317

Immediate Actions Required

• Update Google Chrome to version 147.0.7727.101 or later on all Windows, macOS, and Linux endpoints.
• Restart the browser after the update so the patched binaries are loaded into running sessions.
• Verify managed deployments through Chrome Enterprise policies and confirm rollout via update telemetry.

Patch Information

Google released the fix in the Stable channel update announced on April 15, 2026. Administrators should consult the Google Chrome Stable Update advisory for the full list of bug fixes shipped in 147.0.7727.101. Enterprise environments using Chrome Browser Cloud Management or Group Policy should expedite the update ring for this release given the network-reachable attack vector.

Workarounds

• Restrict access to high-risk websites through web filtering until patching completes.
• Disable the Cast feature in managed environments using the EnableMediaRouter enterprise policy set to false where casting is not required.
• Apply site isolation and strict sandbox policies to limit the impact of renderer compromise.

# Chrome Enterprise policy example: disable Media Router (Cast) on Windows
# HKLM\Software\Policies\Google\Chrome
reg add "HKLM\Software\Policies\Google\Chrome" /v EnableMediaRouter /t REG_DWORD /d 0 /f

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

# Verify installed Chrome version on macOS
/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --version