CVE-2026-7338: Google Chrome Cast Use After Free Flaw

CVE-2026-7338 Overview

CVE-2026-7338 is a use-after-free vulnerability discovered in the Cast component of Google Chrome prior to version 147.0.7727.138. This memory corruption flaw allows an attacker positioned on the local network segment to potentially exploit heap corruption through malicious network traffic. The vulnerability has been assigned a high severity rating by the Chromium security team.

Critical Impact

Attackers on the same network segment can exploit this use-after-free condition to corrupt heap memory, potentially leading to arbitrary code execution within the browser context.

Affected Products

• Google Chrome versions prior to 147.0.7727.138
• Chromium-based browsers using affected Cast component code
• Desktop platforms running vulnerable Chrome versions (Windows, macOS, Linux)

Discovery Timeline

• 2026-04-28 - CVE-2026-7338 published to NVD
• 2026-04-29 - Last updated in NVD database

Technical Details for CVE-2026-7338

Vulnerability Analysis

This vulnerability is classified as CWE-416 (Use After Free), a memory corruption issue that occurs when a program continues to reference memory after it has been freed. In the context of Chrome's Cast component, the flaw manifests during the processing of network traffic related to casting functionality.

The Cast component in Google Chrome handles media streaming and screen mirroring to Chromecast-enabled devices. When processing certain malformed or malicious network packets, the component fails to properly manage object lifetimes, resulting in a dangling pointer that can be exploited.

An attacker with adjacent network access can craft malicious network traffic targeting the Cast component's protocol handlers. When the vulnerable code path is triggered, the freed memory may be reallocated and populated with attacker-controlled data, enabling heap corruption.

Root Cause

The root cause stems from improper memory management in Chrome's Cast component. Specifically, an object is freed prematurely while references to it still exist in the codebase. When subsequent operations attempt to access the freed object through these stale references, heap corruption occurs. This type of vulnerability is particularly dangerous in browser contexts as it can bypass memory protections and lead to code execution.

Attack Vector

The attack vector requires the adversary to be positioned on the same local network segment as the victim. This adjacent network requirement means the attacker must have access to the same LAN, Wi-Fi network, or network segment. The attack can be executed by:

1. Establishing presence on the target's local network
2. Broadcasting or directing malicious Cast-related network traffic
3. Triggering the vulnerable code path in Chrome's Cast component
4. Exploiting the use-after-free condition to corrupt heap memory

The vulnerability does not require user interaction or prior authentication, making it exploitable against any Chrome user on a compromised network segment. However, the complexity of reliable exploitation is considered high due to heap memory layout unpredictability.

Detection Methods for CVE-2026-7338

Indicators of Compromise

• Unusual network traffic patterns targeting Cast/mDNS protocols on the local network
• Unexpected Chrome browser crashes, particularly when Cast functionality is active
• Memory corruption or heap corruption error messages in Chrome crash reports
• Suspicious broadcast or multicast traffic from unknown sources on the network segment

Detection Strategies

• Monitor for anomalous Cast protocol traffic using network intrusion detection systems
• Enable Chrome crash reporting to identify potential exploitation attempts
• Deploy endpoint detection solutions capable of monitoring browser memory integrity
• Implement network segmentation monitoring to detect lateral movement attempts

Monitoring Recommendations

• Configure network monitoring to alert on unusual Cast-related protocol activity
• Enable detailed browser logging to capture potential exploitation indicators
• Monitor for Chrome process anomalies including unexpected child process spawning
• Review Chrome version compliance across the enterprise to identify vulnerable installations

How to Mitigate CVE-2026-7338

Immediate Actions Required

• Update Google Chrome to version 147.0.7727.138 or later immediately
• Verify Chrome auto-update functionality is enabled and working correctly
• Consider disabling Cast functionality temporarily on high-risk systems until patched
• Implement network segmentation to limit exposure from adjacent network attacks

Patch Information

Google has released Chrome version 147.0.7727.138 which addresses this vulnerability. The fix corrects the object lifetime management issue in the Cast component. Organizations should deploy this update through their software management systems immediately.

For detailed patch information, see the Google Chrome Desktop Update announcement. Technical details about the vulnerability can be found in the Chromium Issue Tracker Entry.

Workarounds

• Disable Chrome Cast functionality via enterprise policy (EnableMediaRouter set to false)
• Implement strict network segmentation to isolate workstations from untrusted network segments
• Deploy network access controls to limit broadcast and multicast traffic
• Consider using browser isolation solutions for high-security environments

# Chrome Enterprise Policy to disable Cast (Windows Registry)
# HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome
# EnableMediaRouter = 0

# Linux/macOS managed preferences
# Set "EnableMediaRouter": false in Chrome policy JSON