CVE-2026-11241: Google Chrome Privilege Escalation Flaw

CVE-2026-11241 Overview

CVE-2026-11241 is an input validation vulnerability in the Cast component of Google Chrome versions prior to 149.0.7827.53. An attacker on the same local network segment can deliver a crafted HTML page that triggers privilege escalation in the browser. The flaw is tracked under [CWE-20: Improper Input Validation] and affects Chrome on Windows, macOS, and Linux. While Google rates the Chromium security severity as Low, the NVD scoring reflects a high impact on confidentiality, integrity, and availability when exploitation succeeds. No public exploit is currently available, and the issue is not listed in the CISA Known Exploited Vulnerabilities catalog.

Critical Impact
A local-network attacker can chain a crafted HTML page with the Cast component to escalate privileges within the browser, potentially gaining access to sensitive user data and session state.

Affected Products

Google Chrome prior to 149.0.7827.53
Google Chrome on Microsoft Windows
Google Chrome on Apple macOS and Linux

Discovery Timeline

2026-06-05 - CVE-2026-11241 published to NVD
2026-06-05 - Last updated in NVD database
2026-06 - Google releases fix in the Stable Channel update for desktop

Technical Details for CVE-2026-11241

Vulnerability Analysis

The vulnerability resides in Chrome's Cast feature, which enables users to stream tab content and media to compatible receiver devices over the local network. The Cast component processes data from both web pages and discovered Cast receivers. Insufficient validation of untrusted input allows a crafted HTML page to provide malformed data that the Cast pipeline accepts without proper sanitization. Successful exploitation leads to privilege escalation within the browser process boundary, breaking expected isolation between web content and higher-privileged Cast functionality. The combination of user interaction (UI:R) and adjacent network access (AV:A) reflects a realistic scenario where a victim visits an attacker-controlled page while connected to a network the attacker also reaches.

Root Cause

The root cause is improper validation of untrusted input within the Cast subsystem. Chrome accepts data influenced by the rendered page and by local-network Cast discovery responses without enforcing the validation required to keep that data from crossing privilege boundaries. Refer to Chromium Issue #497203741 for tracking details.

Attack Vector

An attacker must reach the victim through the same local network segment, typically a shared Wi-Fi or LAN environment. The attacker hosts a crafted HTML page and induces the victim to load it. The page interacts with the Cast API in a way that supplies malformed input, leveraging the attacker's local-network position to influence Cast discovery or receiver responses. Once the validation gap is triggered, the attacker gains elevated privileges within the browser context. Synthetic exploit code is not published, and no proof-of-concept has been observed in the wild.

Detection Methods for CVE-2026-11241

Indicators of Compromise

Chrome installations reporting versions earlier than 149.0.7827.53 in enterprise inventory data.
Unexpected Cast session initiations to unknown receivers on user endpoints, particularly on guest or shared networks.
Outbound HTTP/HTTPS requests from Chrome renderer processes to local-network IP ranges immediately after a Cast API call.

Detection Strategies

Inventory browser versions across managed endpoints and flag any Chrome build below 149.0.7827.53.
Monitor process telemetry for anomalous child processes or memory regions spawned by chrome.exe following Cast activity.
Correlate web proxy logs with endpoint Cast usage to identify pages that invoke Cast APIs from untrusted origins.

Monitoring Recommendations

Track Chrome auto-update status and surface endpoints that fail to receive the Stable Channel update.
Alert on lateral connections from user endpoints to non-corporate Cast or mDNS responders on local subnets.
Review network segmentation policies to detect when corporate endpoints share broadcast domains with untrusted devices.

How to Mitigate CVE-2026-11241

Immediate Actions Required

Update Google Chrome to version 149.0.7827.53 or later on all Windows, macOS, and Linux endpoints.
Force a browser restart through endpoint management to ensure the patched binary loads.
Restrict use of corporate devices on untrusted shared networks until patching is verified.

Patch Information

Google addressed the vulnerability in the Stable Channel desktop release documented in the Chrome Releases blog. Administrators should confirm deployment through Chrome Browser Cloud Management or equivalent endpoint tooling. Additional technical context is available in Chromium Issue #497203741.

Workarounds

Disable the Cast feature via the EnableMediaRouter enterprise policy where Cast functionality is not required.
Block outbound mDNS and Cast discovery traffic (UDP/5353, TCP/8008-8009) on networks where Cast is not authorized.
Use network segmentation to prevent corporate endpoints from sharing layer-2 domains with untrusted devices.

bash

# Chrome enterprise policy example to disable Media Router / Cast
# Windows registry path:
# HKLM\Software\Policies\Google\Chrome\EnableMediaRouter = 0

# macOS plist example:
defaults write com.google.Chrome EnableMediaRouter -bool false

# Linux managed policy (/etc/opt/chrome/policies/managed/cast.json):
{
  "EnableMediaRouter": false
}