CVE-2026-6313: Google Chrome CORS Information Disclosure

CVE-2026-6313 Overview

CVE-2026-6313 is an insufficient policy enforcement vulnerability in the Cross-Origin Resource Sharing (CORS) implementation of Google Chrome prior to version 147.0.7727.101. A remote attacker who has already compromised the renderer process can leak cross-origin data by serving a crafted HTML page to the victim. The flaw is classified under [CWE-284] Improper Access Control. Chromium engineers rated the internal security severity as High, while the NVD CVSS v3.1 score reflects a lower exploitability profile due to the prerequisite of renderer compromise and required user interaction.

Critical Impact
Successful exploitation enables disclosure of cross-origin data, undermining the same-origin policy that isolates web applications within the browser.

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 - CVE-2026-6313 published to NVD
2026-04-15 - Google releases stable channel update addressing the issue
2026-04-17 - Last updated in NVD database

Technical Details for CVE-2026-6313

Vulnerability Analysis

The vulnerability resides in how Chrome enforces CORS policy decisions between the renderer and network service. CORS is the browser mechanism that controls when one origin may read responses returned by another origin. Chrome's site isolation model assumes that CORS checks performed in or relayed through a compromised renderer cannot be trusted, so authoritative enforcement must occur in the privileged browser process. Insufficient enforcement in this boundary allows an attacker controlling a renderer to influence policy outcomes and read responses that should remain opaque.

Because the bug requires a pre-compromised renderer, it is typically chained behind a separate renderer exploit such as a memory corruption or type confusion flaw. On its own, the issue does not yield code execution, but it weakens a core web security boundary and is valuable as part of a multi-stage browser exploit chain.

Root Cause

The root cause is improper access control [CWE-284] in CORS policy enforcement. The browser does not adequately validate or re-check cross-origin response handling decisions when requests originate from a renderer process operating outside its expected security constraints.

Attack Vector

Exploitation requires a remote attacker to first compromise the renderer process, then deliver a crafted HTML page that triggers cross-origin fetches whose responses are improperly exposed back to attacker-controlled JavaScript. User interaction, such as visiting a malicious page, is required. No verified public proof-of-concept code is available for this issue. See the Chromium Issue Tracker #498765210 for further technical context.

Detection Methods for CVE-2026-6313

Indicators of Compromise

Chrome browser processes running versions earlier than 147.0.7727.101 within the environment.
Unexpected outbound requests from browser processes to attacker-controlled domains following navigation to untrusted pages.
Renderer process crashes or anomalies preceding cross-origin data access patterns.

Detection Strategies

Inventory installed Chrome versions across Windows, macOS, and Linux endpoints and flag any build below 147.0.7727.101.
Monitor proxy and DNS logs for browser-initiated connections to newly registered or low-reputation domains hosting HTML payloads.
Correlate renderer process anomalies with subsequent network egress to identify potential exploit chains targeting the browser.

Monitoring Recommendations

Enforce browser version telemetry through endpoint management and centralize results in a SIEM for compliance reporting.
Alert on Chrome child processes spawning unusual descendants or making sensitive API calls shortly after a page load event.
Track web proxy events for repeated cross-origin fetches that deviate from baseline application behavior.

How to Mitigate CVE-2026-6313

Immediate Actions Required

Update Google Chrome to version 147.0.7727.101 or later on all Windows, macOS, and Linux endpoints.
Verify enterprise update channels and managed Chrome policies are not blocking the stable channel rollout.
Restart browser sessions after patch deployment to ensure the updated binaries are loaded.

Patch Information

Google addressed CVE-2026-6313 in the Chrome stable channel update detailed in the Google Chrome Desktop Update advisory. The fixed version is 147.0.7727.101. Chromium-based browsers that incorporate the upstream fix should also be updated to their corresponding patched releases.

Workarounds

Apply the vendor patch — no supported configuration workaround eliminates the underlying CORS enforcement gap.
Restrict browsing to trusted sites through enterprise URL allowlists until patching is complete.
Deploy Chrome enterprise policies that disable unnecessary extensions and reduce attack surface on the renderer process.

bash

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

# Example minimum required version check
# Expected output: Google Chrome 147.0.7727.101 or later