CVE-2026-11289: Google Chrome Information Disclosure Bug

CVE-2026-11289 Overview

CVE-2026-11289 is a side-channel information leakage vulnerability in the Paint component of Google Chrome versions prior to 149.0.7827.53. A remote attacker can leak cross-origin data by serving a crafted HTML page to a victim. The flaw is classified under CWE-1300 (Improper Protection of Physical Side Channels) and CWE-203 (Observable Discrepancy). Chromium maintainers rated the underlying security severity as Low, while the NVD assigned a CVSS 3.1 score of 6.5 due to the high confidentiality impact on cross-origin resources.

Critical Impact
A remote attacker can exfiltrate cross-origin data rendered by Chrome's Paint pipeline, breaking same-origin policy assumptions when a user visits a malicious page.

Affected Products

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

Discovery Timeline

2026-06-05 - CVE-2026-11289 published to NVD
2026-06-09 - Last updated in NVD database

Technical Details for CVE-2026-11289

Vulnerability Analysis

The vulnerability resides in Chrome's Paint subsystem, which is responsible for rasterizing and compositing graphical content from the Document Object Model (DOM). The Paint pipeline processes cross-origin resources such as images, iframes, and SVG content within an isolated rendering context. A timing or observable-discrepancy side channel in this pipeline allows an attacker-controlled page to infer properties of cross-origin pixels.

By hosting a crafted HTML page that embeds cross-origin content and observes Paint behavior, an attacker can reconstruct data the browser is meant to protect. This includes inferring rendered pixel values, document state, or other cross-origin artifacts that should remain isolated under the same-origin policy. User interaction is required: the victim must visit or interact with the attacker's page.

Root Cause

The root cause aligns with [CWE-203] (Observable Discrepancy) and [CWE-1300] (Improper Protection of Physical Side Channels). The Paint code path produced measurable behavioral differences when handling cross-origin content versus same-origin content. An attacker observes those differences from JavaScript and reconstructs protected data without ever reading it directly through a sanctioned API.

Attack Vector

Exploitation is remote and unauthenticated. The attacker delivers a crafted HTML page to the target, typically through phishing, malvertising, or a watering-hole compromise. When the victim loads the page in a vulnerable Chrome build, the embedded JavaScript triggers paint operations against cross-origin resources and measures the resulting discrepancies. No verified proof-of-concept is publicly available, and CISA has not added this CVE to the Known Exploited Vulnerabilities catalog. Technical details are tracked in Chromium Bug Report #502239897.

Detection Methods for CVE-2026-11289

Indicators of Compromise

Chrome browser processes loading attacker-controlled HTML that embeds cross-origin iframes, images, or SVG resources from unusual third-party origins.
Outbound HTTP(S) connections from chrome.exe to newly registered or low-reputation domains immediately followed by sustained CPU activity in the renderer process.
Browser telemetry showing Chrome versions earlier than 149.0.7827.53 in the enterprise fleet.

Detection Strategies

Inventory installed Chrome versions across Windows, macOS, and Linux endpoints and flag any host running a build older than 149.0.7827.53.
Monitor web proxy logs for users visiting domains that serve heavily scripted cross-origin embedding patterns, particularly pages combining many iframes with timing-sensitive JavaScript.
Correlate browser process telemetry with DNS and TLS metadata to surface sessions where renderer processes contact unrelated third-party origins shortly after a phishing email click.

Monitoring Recommendations

Enable browser management policies that report installed version and update channel to a central console.
Forward endpoint and proxy logs to a centralized data lake to support retrospective hunts once additional indicators emerge.
Track the Google Chrome Update Announcement feed to confirm patch deployment status.

How to Mitigate CVE-2026-11289

Immediate Actions Required

Update Google Chrome to version 149.0.7827.53 or later on all Windows, macOS, and Linux endpoints.
Restart Chrome after the update to ensure the patched renderer and Paint components are loaded.
Verify auto-update is enabled and not blocked by enterprise policy or network filtering.

Patch Information

Google addressed CVE-2026-11289 in Chrome Stable channel build 149.0.7827.53. Patch details and rollout information are documented in the Google Chrome Update Announcement, and the underlying issue is tracked in Chromium Bug Report #502239897. Chromium-derived browsers such as Microsoft Edge, Brave, and Opera should be updated once their vendors ship the equivalent fix.

Workarounds

Restrict browsing to trusted sites using URL filtering or DNS-based controls until patches are deployed.
Apply enterprise browser policies that disable or limit third-party iframe and cross-origin embedding on high-risk user groups.
Increase user awareness of phishing lures that direct victims to attacker-hosted pages, since exploitation requires user interaction.

bash

# Verify Chrome version on Linux/macOS endpoints
google-chrome --version

# Windows PowerShell: check installed Chrome version
(Get-Item "$env:ProgramFiles\Google\Chrome\Application\chrome.exe").VersionInfo.ProductVersion

# Force an update check via Chrome's internal URL (open in browser)
# chrome://settings/help