CVE-2026-13021: Google Chrome Auth Bypass Vulnerability

CVE-2026-13021 Overview

CVE-2026-13021 is a same-origin policy bypass affecting Google Chrome versions prior to 149.0.7827.197. The flaw resides in the DeviceBoundSessionCredentials implementation, where inappropriate handling allows a remote attacker to circumvent same-origin restrictions through a crafted HTML page. The Chromium project rated the underlying security severity as High, while the NVD assigns a medium CVSS score reflecting the requirement for user interaction. Exploitation requires the victim to visit attacker-controlled content. Successful attacks compromise confidentiality of data across origins without altering integrity or availability. The vulnerability is tracked under [CWE-346: Origin Validation Error].

Critical Impact
Remote attackers can bypass the same-origin policy through a crafted HTML page, exposing cross-origin data tied to device-bound session credentials.

Affected Products

Google Chrome Desktop versions prior to 149.0.7827.197
Chromium-based browsers incorporating the affected DeviceBoundSessionCredentials implementation
All operating system platforms running vulnerable Chrome builds (Windows, macOS, Linux)

Discovery Timeline

2026-06-24 - CVE-2026-13021 published to NVD
2026-06-25 - Last updated in NVD database

Technical Details for CVE-2026-13021

Vulnerability Analysis

The vulnerability stems from an inappropriate implementation within Chrome's DeviceBoundSessionCredentials feature. Device Bound Session Credentials (DBSC) bind authentication sessions to cryptographic keys held by the device, mitigating session token theft. The affected logic fails to correctly enforce same-origin policy checks when handling credential-bound session operations. A crafted HTML page can leverage this gap to access resources or session state associated with a different origin. The browser treats certain cross-origin interactions as permissible when they should be blocked. This breaks one of the foundational web security boundaries that isolates content between websites.

Root Cause

The root cause maps to [CWE-346: Origin Validation Error]. The DeviceBoundSessionCredentials code path does not adequately validate the origin of the requesting context before performing privileged session credential operations. Origin checks are either missing, executed against the wrong context, or applied inconsistently across credential-handling code paths.

Attack Vector

The attack is network-based and requires user interaction. A victim must visit or be redirected to an attacker-controlled web page. The page contains crafted HTML and script that exercise the flawed DBSC code path to read or interact with cross-origin session state. No prior authentication or special privileges are required on the attacker side. Refer to the Chromium Issue Tracker #511776603 and the Google Chrome Desktop Update for vendor-supplied technical context.

Detection Methods for CVE-2026-13021

Indicators of Compromise

Outbound browser connections to unfamiliar domains immediately following navigation to untrusted links or advertisements
Browser telemetry showing endpoint clients on Chrome versions earlier than 149.0.7827.197
Unexpected cross-origin requests targeting endpoints associated with device-bound session establishment

Detection Strategies

Inventory installed Chrome versions across the fleet using endpoint management or EDR telemetry and flag any build below 149.0.7827.197
Monitor proxy and DNS logs for users visiting newly registered or low-reputation domains hosting active scripts
Correlate browser process activity with authentication anomalies on internal services that rely on session cookies or DBSC

Monitoring Recommendations

Ingest browser version and patch-state telemetry into the SIEM for continuous compliance reporting
Alert on Chrome process spawning child processes or accessing credential stores after visits to untrusted origins
Track authentication events for impossible-travel or session reuse patterns that may indicate credential abuse

How to Mitigate CVE-2026-13021

Immediate Actions Required

Update Google Chrome to version 149.0.7827.197 or later on all managed endpoints
Force-restart Chrome after deployment to ensure the patched binary is loaded into memory
Verify Chromium-based browsers in the environment have absorbed the upstream fix before declaring remediation complete

Patch Information

Google released the fix in Chrome Stable channel version 149.0.7827.197. Deployment details are available in the Google Chrome Desktop Update announcement. Administrators should push the update through enterprise management policies such as Chrome Browser Cloud Management, Group Policy, or MDM profiles. The corresponding upstream tracking record is the Chromium Issue Tracker #511776603.

Workarounds

Restrict browsing to trusted sites via web filtering or DNS-layer controls until patching completes
Educate users to avoid clicking unsolicited links, especially those delivered through email or messaging platforms
Where feasible, temporarily disable experimental DBSC-related Chrome flags on managed devices pending update rollout

bash

# Verify installed Chrome version on Linux/macOS endpoints
google-chrome --version
# Expected output (or higher): Google Chrome 149.0.7827.197

# Windows: query the installed Chrome version from the registry
reg query "HKLM\Software\Google\Update\Clients\{8A69D345-D564-463C-AFF1-A69D9E530F96}" /v pv