CVE-2026-79076: Google Chrome Sync Information Disclosure

CVE-2026-79076 Overview

CVE-2026-79076 is an improper input validation vulnerability [CWE-20] in the Sync component of Google Chrome. Versions prior to 152.0.7977.65 fail to properly validate incoming network data processed by the Sync service. A remote attacker can craft malicious network traffic to obtain sensitive information from a targeted Chrome user. The Chromium project rates the security severity as Medium. Exploitation requires user interaction, and the attack vector is network-based. Google has addressed the flaw in the Stable channel update for desktop.

Critical Impact
Successful exploitation exposes confidential user data synchronized through Chrome, enabling information disclosure without impacting integrity or availability.

Affected Products

Google Chrome for Desktop prior to 152.0.7977.65
Chromium-based browsers incorporating the vulnerable Sync component
Any downstream distribution shipping Chrome versions below 152.0.7977.65

Discovery Timeline

2026-08-25 - CVE-2026-79076 published to the National Vulnerability Database
2026-08-26 - Last updated in NVD database

Technical Details for CVE-2026-79076

Vulnerability Analysis

The vulnerability resides in the Chrome Sync subsystem, which synchronizes bookmarks, history, passwords, and other browser state across a user's devices. Chrome does not adequately validate certain fields within crafted network traffic destined for the Sync client. An attacker who can influence sync-related network responses can trigger the input validation flaw and cause the browser to leak sensitive information back over the network. The Chromium issue tracker entry #496395158 corresponds to this defect and remains restricted pending broader patch adoption.

Root Cause

The root cause is improper input validation [CWE-20] within the Sync component's message handling path. Fields parsed from remote sync traffic are not sufficiently constrained before being used, which allows unexpected inputs to influence data handling in ways that expose confidential state. The defect is contained within the browser process's sync logic rather than the renderer sandbox.

Attack Vector

Exploitation is remote and requires user interaction, consistent with the vulnerability's network attack vector. An attacker must induce the victim's Chrome instance to process crafted sync traffic, for example through a compromised or malicious upstream service, a network-level adversary, or a lure that causes the browser to interact with attacker-controlled content. Successful exploitation results in disclosure of sensitive information but does not alter data or crash the browser.

No public proof-of-concept is available. Google restricts detailed technical disclosure until the patch is broadly deployed. Refer to the Chromium Issue Tracker #496395158 for the vendor's advisory reference.

Detection Methods for CVE-2026-79076

Indicators of Compromise

Chrome instances reporting a browser version below 152.0.7977.65 in endpoint inventory telemetry.
Unexpected outbound connections from chrome.exe to non-Google-owned hosts serving sync-like traffic patterns.
Anomalous volume or timing of clients4.google.com or sync endpoint communications originating from user devices.

Detection Strategies

Query endpoint inventory data to identify hosts running Chrome versions preceding the fixed build 152.0.7977.65.
Inspect proxy and DNS logs for browser sync traffic redirected to unauthorized destinations.
Correlate browser process network activity with known Google sync infrastructure to surface deviations.

Monitoring Recommendations

Enforce continuous browser version reporting through enterprise management tooling such as Chrome Browser Cloud Management.
Monitor TLS SNI and destination IP telemetry for Chrome sync sessions terminating at non-Google endpoints.
Alert on Group Policy changes that disable Chrome auto-update or modify sync URL overrides.

How to Mitigate CVE-2026-79076

Immediate Actions Required

Update Google Chrome to version 152.0.7977.65 or later on all managed endpoints.
Verify that Chrome auto-update is enabled and functioning across the fleet.
Restart Chrome after patch deployment to ensure the vulnerable Sync code path is unloaded.

Patch Information

Google released the fix in the Stable channel update for desktop announced on the Chrome Releases blog. Administrators should deploy Chrome 152.0.7977.65 or later. See the Google Chrome Stable Update announcement for release details.

Workarounds

Disable Chrome Sync through the SyncDisabled enterprise policy until patched builds are deployed.
Restrict outbound browser traffic to Google sync endpoints via egress filtering where feasible.
Enforce browser version compliance policies that quarantine hosts running builds prior to 152.0.7977.65.

bash

# Example: enforce SyncDisabled via Chrome enterprise policy on Windows
reg add "HKLM\SOFTWARE\Policies\Google\Chrome" /v SyncDisabled /t REG_DWORD /d 1 /f

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