CVE-2026-15775: Google Chrome Auth Bypass Vulnerability

CVE-2026-15775 Overview

CVE-2026-15775 is a same-origin policy (SOP) bypass vulnerability in the V8 JavaScript engine used by Google Chrome. Versions prior to 150.0.7871.125 are affected. A remote attacker can exploit the flaw by convincing a user to visit a crafted HTML page. Chromium's security team rated the underlying issue as High severity, though the NVD scoring reflects Medium severity because exploitation requires user interaction and impacts integrity only.

The weakness is tracked under CWE-346: Origin Validation Error. Successful exploitation allows attacker-controlled scripts to interact with content from other origins, undermining a core browser security boundary.

Critical Impact
Attackers can bypass the same-origin policy to read or manipulate cross-origin data, enabling credential theft, session hijacking, and account takeover from a single malicious page visit.

Affected Products

Google Chrome (Desktop) versions prior to 150.0.7871.125
Chromium-based browsers embedding vulnerable V8 builds
Any application using the affected V8 engine version

Discovery Timeline

2026-07-14 - CVE CVE-2026-15775 published to NVD
2026-07-15 - Last updated in NVD database

Technical Details for CVE-2026-15775

Vulnerability Analysis

The flaw resides in V8, the JavaScript and WebAssembly engine that powers Chrome. V8 fails to correctly enforce origin checks during a specific execution path, allowing script contexts from one origin to reach into resources belonging to another. This defeats the same-origin policy, the foundational browser primitive that isolates content served by different sites.

The vulnerability requires user interaction. A victim must load an attacker-controlled HTML page, at which point embedded JavaScript triggers the flawed V8 code path. No authentication is required, and the attack is delivered entirely over the network.

Because the issue impacts integrity but not confidentiality or availability in the NVD scoring, the practical outcome is unauthorized cross-origin data access and manipulation. Attackers commonly chain SOP bypasses to steal authentication tokens, read cross-site responses, or perform actions in the victim's authenticated sessions.

Root Cause

Google's advisory categorizes the defect as an "inappropriate implementation" in V8, which typically indicates a logic error rather than a memory safety bug. The engine's origin validation logic does not correctly identify or enforce the security boundary between contexts. This maps to CWE-346: Origin Validation Error, where a component does not sufficiently verify that a request or resource originates from a trusted source.

Attack Vector

Exploitation follows a standard drive-by pattern. The attacker hosts a crafted HTML page containing JavaScript that invokes the vulnerable V8 code path. The victim visits the page through phishing, malvertising, or a compromised legitimate site. Once loaded, the script reads or modifies data from another origin the victim is authenticated to, such as webmail, banking, or SaaS applications.

Refer to the Chromium Issue Tracker Entry and the Google Chrome Stable Channel Update for vendor-published technical context.

Detection Methods for CVE-2026-15775

Indicators of Compromise

Chrome browser processes running versions earlier than 150.0.7871.125 after the patch release date
Outbound requests from browser sessions to newly registered or low-reputation domains hosting HTML pages with heavy inline JavaScript
Unexpected cross-origin data flows in browser telemetry, such as fetch or XMLHttpRequest calls returning data from unrelated origins

Detection Strategies

Inventory installed Chrome versions across managed endpoints and flag any instance below 150.0.7871.125
Monitor endpoint DNS and proxy logs for user navigation to suspicious HTML landing pages preceding anomalous authentication events
Correlate browser telemetry with identity provider logs to spot session hijacking following visits to untrusted sites

Monitoring Recommendations

Enable enterprise browser reporting or the Chrome Enterprise Connectors framework to centralize browser version and extension telemetry
Alert on account activity originating from unexpected geolocations or user agents shortly after users browse external sites
Track patch compliance via configuration management tools and generate weekly exception reports for unpatched hosts

How to Mitigate CVE-2026-15775

Immediate Actions Required

Update Google Chrome to version 150.0.7871.125 or later on all Windows, macOS, and Linux endpoints
Restart Chrome after the update installs to ensure the patched V8 binary is loaded into memory
Audit Chromium-based browsers and embedded WebView components for updates from their respective vendors

Patch Information

Google released the fix in the Chrome Stable channel with version 150.0.7871.125. Details are published in the Chrome Releases blog. Enterprise administrators should push the update through their standard Chrome update infrastructure or managed software distribution tooling.

Workarounds

Enforce Chrome auto-update via ChromeCleanupEnabled and UpdateDefault policies to prevent version drift
Restrict browsing to trusted sites through URL allowlists for high-risk user populations until patching completes
Deploy browser isolation or remote browser technology for users who access sensitive internal applications

bash

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

# Verify installed Chrome version on Windows (PowerShell)
(Get-Item "C:\Program Files\Google\Chrome\Application\chrome.exe").VersionInfo.ProductVersion

# Example Chrome Enterprise policy to enforce updates (JSON)
{
  "UpdateDefault": 1,
  "AutoUpdateCheckPeriodMinutes": 60,
  "TargetVersionPrefix": "150.0.7871.125"
}