CVE-2026-13921: Google Chrome Auth Bypass Vulnerability

CVE-2026-13921 Overview

CVE-2026-13921 is an input validation vulnerability in the DeviceBoundSessionCredentials component of Google Chrome. Versions prior to 150.0.7871.47 fail to properly validate untrusted input, allowing a remote attacker to bypass the same origin policy through a crafted HTML page. The flaw is classified under [CWE-20: Improper Input Validation]. Successful exploitation requires user interaction, such as visiting a malicious page. Google rates the Chromium security severity as Medium.

Critical Impact
A remote attacker can bypass the same origin policy and compromise the integrity of cross-origin data by luring a user to a crafted HTML page.

Affected Products

Google Chrome versions prior to 150.0.7871.47
Chromium-based browsers sharing the affected DeviceBoundSessionCredentials implementation
Desktop platforms (Windows, macOS, Linux) served by the Stable channel update

Discovery Timeline

2026-06-30 - CVE-2026-13921 published to NVD
2026-07-01 - Last updated in NVD database

Technical Details for CVE-2026-13921

Vulnerability Analysis

The vulnerability resides in Chrome's DeviceBoundSessionCredentials (DBSC) feature, which binds session credentials to a specific device using hardware-backed keys. The component fails to sufficiently validate untrusted input supplied through web content. This gap permits an attacker to influence credential handling in a way that violates the same origin policy, one of the browser's foundational security boundaries.

The same origin policy isolates documents and scripts loaded from different origins. Bypassing it enables an attacker-controlled page to influence or observe interactions bound to a different origin. The integrity impact is High, while confidentiality and availability are not directly affected according to the CVSS vector.

Root Cause

The root cause is improper input validation [CWE-20] in the DeviceBoundSessionCredentials code path. Data derived from a remote HTML document is consumed without adequate checks on origin, structure, or type. Because DBSC ties session state to the browser instance, weak validation lets an attacker steer session-bound operations across origin boundaries.

Attack Vector

Exploitation is remote and requires user interaction. An attacker hosts a crafted HTML page and induces a victim running a vulnerable Chrome build to load it. The page delivers malformed input to the DeviceBoundSessionCredentials interface, coercing the browser into treating attacker-controlled content as trusted within another origin's context.

No authentication is required, attack complexity is low, and no privileges are needed. Public proof-of-concept exploit code is not currently available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. See the Chromium Issue Tracker Entry for additional technical context.

Detection Methods for CVE-2026-13921

Indicators of Compromise

Chrome browser processes running versions earlier than 150.0.7871.47 in enterprise inventory scans
Outbound connections from browser processes to unfamiliar domains immediately after visiting a suspicious link
Anomalous DBSC session key operations or repeated credential rebinding events in browser telemetry

Detection Strategies

Inventory installed Chrome versions across managed endpoints and flag builds below 150.0.7871.47
Inspect proxy and DNS logs for user navigation to newly registered or low-reputation domains hosting HTML payloads
Correlate browser child process activity with unexpected cross-origin credential flows recorded in web application logs

Monitoring Recommendations

Enable Chrome enterprise reporting to centralize version, extension, and crash data
Monitor authentication logs on high-value web applications for session anomalies that could indicate same origin policy bypass
Track user-reported phishing pages and correlate with endpoint browsing telemetry

How to Mitigate CVE-2026-13921

Immediate Actions Required

Update Google Chrome to version 150.0.7871.47 or later on all managed endpoints
Force-restart Chrome sessions after deployment to ensure the patched binary is loaded
Audit Chromium-based browsers in the environment for equivalent upstream fixes

Patch Information

Google addressed the flaw in the Stable channel release documented in the Google Chrome Update Blog. Administrators should deploy Chrome 150.0.7871.47 or later through their standard software distribution process. The fix strengthens input validation within the DeviceBoundSessionCredentials component to enforce origin boundaries.

Workarounds

Restrict user browsing to trusted sites through web filtering while patches propagate
Enforce Chrome auto-update policies so that Stable channel updates apply without user delay
Provide targeted user awareness communications about clicking unsolicited links, since exploitation requires user interaction

bash

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

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