CVE-2026-11298: Google Chrome iOS Auth Bypass Vulnerability

CVE-2026-11298 Overview

CVE-2026-11298 is a same-origin policy bypass affecting Google Chrome for iOS versions prior to 149.0.7827.53. The vulnerability stems from an inappropriate implementation in the Chrome for iOS browser component. A remote attacker can exploit this flaw by serving a crafted HTML page to a victim. Successful exploitation allows the attacker to bypass the same-origin policy, a foundational web security boundary that isolates content from different origins. The issue is categorized under [CWE-346] Origin Validation Error. Chromium rates this as low severity internally, while the NVD assigns a medium CVSS rating reflecting limited integrity impact.

Critical Impact
Attackers can bypass same-origin policy in Chrome for iOS, enabling cross-origin data access through a malicious web page that requires only user interaction to load.

Affected Products

Google Chrome for iOS prior to 149.0.7827.53
Apple iPhone OS (as the underlying platform for Chrome iOS builds)
Any iOS device running a vulnerable Chrome version

Discovery Timeline

2026-06-05 - CVE-2026-11298 published to NVD
2026-06-09 - Last updated in NVD database

Technical Details for CVE-2026-11298

Vulnerability Analysis

The vulnerability resides in Chrome for iOS, Google's browser build that wraps Apple's WebKit engine due to iOS App Store restrictions. The flaw enables a remote attacker to bypass the same-origin policy (SOP) through a crafted HTML page. The same-origin policy restricts how scripts loaded from one origin can interact with resources from another origin. Bypassing it allows a malicious page to read or manipulate data tied to a different origin loaded in the same browser context. The attack requires user interaction, typically convincing the target to visit an attacker-controlled URL. Confidentiality is not directly impacted per the CVSS vector, but integrity of cross-origin interactions is degraded. Exploitation does not require authentication or elevated privileges on the target device.

Root Cause

The root cause is an origin validation error [CWE-346] in how Chrome for iOS processes specific HTML constructs. The browser fails to correctly enforce origin boundaries when handling the crafted page, permitting cross-origin operations that should be blocked. Public technical detail remains limited as the Chromium issue tracker entry restricts access to non-sensitive content during disclosure.

Attack Vector

The attack vector is network-based with low complexity. An attacker hosts a crafted HTML page and lures a user of vulnerable Chrome for iOS to load it through phishing, malvertising, or a compromised site. Once loaded, the page exercises the implementation flaw to interact with resources outside its origin. No additional payload delivery or privilege escalation is needed for the same-origin bypass itself. The vulnerability mechanism is described in prose because no verified proof-of-concept code has been published. Refer to the Chrome Release Update Blog and the Chromium Issue Tracker Entry for vendor-provided context.

Detection Methods for CVE-2026-11298

Indicators of Compromise

iOS devices running Chrome versions prior to 149.0.7827.53 connecting to unfamiliar HTML resources hosted on low-reputation domains.
Browser telemetry showing unexpected cross-origin reads or postMessage activity originating from recently visited pages.
Phishing or malvertising URLs delivered via SMS, email, or messaging apps targeting iOS Chrome users.

Detection Strategies

Inventory mobile devices and identify endpoints running Chrome for iOS below 149.0.7827.53 using mobile device management (MDM) reporting.
Monitor egress proxy and DNS logs for connections to known malicious or newly registered domains serving HTML payloads to iOS user agents.
Correlate web gateway alerts on crafted HTML responses with iOS Chrome user-agent strings to surface targeted browsing sessions.

Monitoring Recommendations

Enable detailed URL and user-agent logging at the network perimeter for mobile traffic to retain forensic context.
Track Chrome version distribution across the iOS fleet and alert when devices remain below 149.0.7827.53 after the patch window.
Subscribe to the Chromium security release feed to receive prompt notification of follow-on advisories tied to the same component.

How to Mitigate CVE-2026-11298

Immediate Actions Required

Update Google Chrome for iOS to version 149.0.7827.53 or later through the Apple App Store on all managed and personal devices.
Push the update via MDM where supported and enforce minimum browser version policies for corporate access.
Educate users to avoid following unsolicited links on iOS devices until updates are verified.

Patch Information

Google addressed CVE-2026-11298 in Chrome for iOS 149.0.7827.53. Details are available in the Chrome Release Update Blog. The fix corrects the origin validation logic in the affected Chrome for iOS component. The corresponding tracking entry is the Chromium Issue Tracker Entry.

Workarounds

Use an alternate, fully patched browser on iOS until Chrome can be updated to 149.0.7827.53.
Restrict access to corporate web applications from iOS Chrome instances below the fixed version through conditional access policies.
Block known malicious domains at the DNS or secure web gateway layer to reduce exposure to crafted HTML pages.

bash

# Configuration example: enforce minimum Chrome iOS version via MDM compliance policy
# (pseudocode for an MDM configuration profile)
mdm policy set browser.chrome_ios.min_version "149.0.7827.53"
mdm policy set compliance.action_below_min_version "block_corporate_access"
mdm policy apply --group "ios-fleet"