CVE-2026-79242 Overview
CVE-2026-79242 is an observable discrepancy vulnerability in the HTML component of Google Chrome versions prior to 152.0.7977.65. A remote attacker can use a crafted HTML page to observe side-channel differences and obtain sensitive information from the browser. The issue is classified under CWE-203: Observable Discrepancy, which covers information leakage caused by behavioral or timing differences that expose internal state to an unprivileged observer. Chromium rates the security severity as Medium. Exploitation requires user interaction, such as visiting an attacker-controlled or compromised page.
Critical Impact
A remote attacker can leak sensitive information from a victim's Chrome browser by delivering a crafted HTML page that triggers an observable discrepancy in HTML processing.
Affected Products
- Google Chrome Desktop prior to 152.0.7977.65
- Chromium-based builds that share the affected HTML rendering path
- Downstream browsers embedding vulnerable Chromium versions
Discovery Timeline
- 2026-08-25 - CVE-2026-79242 published to NVD
- 2026-08-26 - Last updated in NVD database
Technical Details for CVE-2026-79242
Vulnerability Analysis
The defect lives in Chrome's HTML processing logic, where a difference in observable behavior discloses information that should remain isolated between origins or documents. Observable discrepancy issues, categorized as [CWE-203], typically expose internal state through variations in timing, error messages, layout, or resource behavior. In a browser context, such discrepancies can undermine same-origin policy guarantees and site isolation. The Chromium project describes the outcome as sensitive information disclosure to a remote attacker, without integrity or availability impact. Exploitation is not straightforward because it depends on precise conditions in the victim's rendering environment, but a successful attack yields data an attacker could not otherwise read across the origin boundary.
Root Cause
The root cause is a distinguishable behavior in HTML handling that varies based on data the attacker is not authorized to observe. That variation, whether a timing gap, a rendering artifact, or a state-dependent response, becomes a signal an attacker can measure from an attacker-controlled document. Further technical details are tracked in the Chromium Issue Tracker Entry.
Attack Vector
Exploitation is network-based and requires the victim to load attacker-controlled content. A user visits a malicious page, clicks a link, or renders an embedded frame that hosts the crafted HTML. The page probes the discrepancy repeatedly to reconstruct sensitive information from the browser or another origin. No credentials are required on the target, but user interaction is necessary and the attack complexity is high. See the Google Chrome Desktop Update for the vendor's release notes.
No verified proof-of-concept code is available for CVE-2026-79242.
Refer to the Chromium Issue Tracker entry linked above for technical details.
Detection Methods for CVE-2026-79242
Indicators of Compromise
- No public indicators of compromise have been published for CVE-2026-79242 as of the last NVD update.
- Presence of Chrome desktop builds below 152.0.7977.65 in endpoint inventory is the primary exposure indicator.
- Unexpected outbound connections from browser processes to unfamiliar domains hosting HTML content warrant review.
Detection Strategies
- Inventory browser versions across managed endpoints and flag any Chrome or Chromium-based build older than 152.0.7977.65.
- Monitor web proxy and DNS telemetry for user navigation to newly registered or low-reputation domains delivering unusual HTML payloads.
- Correlate browser process telemetry with EPSS and vulnerability management data to prioritize unpatched hosts.
Monitoring Recommendations
- Alert on Chrome auto-update failures or disabled update services that leave endpoints stuck below 152.0.7977.65.
- Track user-interaction events, such as click-through to external links from email or messaging apps, that lead to unpatched browsers.
- Review browser crash and renderer telemetry for anomalies that could indicate discrepancy probing.
How to Mitigate CVE-2026-79242
Immediate Actions Required
- Update Google Chrome Desktop to version 152.0.7977.65 or later on all managed endpoints.
- Restart Chrome after the update so the patched renderer and HTML pipeline are loaded.
- Identify Chromium-based applications in the environment and apply vendor updates that incorporate the fixed Chromium version.
Patch Information
Google addressed CVE-2026-79242 in the Chrome Stable channel release documented in the Google Chrome Desktop Update. The fixed version is 152.0.7977.65. Administrators should validate that Chrome's automatic update mechanism is enabled and functioning, and push the update through enterprise management tooling where auto-update is restricted.
Workarounds
- Restrict browsing to trusted sites through web filtering until patching completes, since exploitation requires loading a crafted HTML page.
- Enforce site isolation and keep default Chrome security settings enabled to reduce cross-origin exposure.
- Disable or limit third-party Chromium-based browsers that have not yet integrated the upstream fix.
# Verify Chrome version on Linux endpoints
google-chrome --version
# Force policy-based update check on Windows via Group Policy Preferences
# Ensure the following registry value is set:
# HKLM\SOFTWARE\Policies\Google\Update\AutoUpdateCheckPeriodMinutes = non-zero
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
