CVE-2026-125347: Chrome FileSystem RCE

Detection Guidance

Start with exposure identification. Browser inventory should identify every Chrome installation below 157.0.8103.50, including laptops that connect intermittently, virtual desktops, kiosks, developer workstations, and unmanaged endpoints accessing corporate services.

Prioritize systems used by administrators, finance personnel, executives, and users with access to sensitive data.

Compromise detection is more difficult because the available research does not provide exploit-specific indicators, payload hashes, URL patterns, or a reliable network signature. A malicious page may be hosted on an otherwise legitimate service, and post-exploitation behavior will vary by payload.

Detection should therefore focus on:

• Chrome spawning unexpected child processes.
• Unusual script interpreters launched by the browser.
• Suspicious files written to temporary directories.
• Browser activity followed by persistence or credential access.
• Unexpected outbound connections immediately after visiting untrusted content.
• New scheduled tasks, services, startup entries, or user-level persistence.

Windows Detection Query

On Windows, hunt for Chrome spawning processes that are uncommon in normal browser workflows. The following Kusto Query Language example is a starting point for Microsoft Defender or a compatible endpoint telemetry platform:

DeviceProcessEvents
| where InitiatingProcessFileName in~ ("chrome.exe", "chrome_proxy.exe")
| where FileName in~ (
    "powershell.exe",
    "pwsh.exe",
    "cmd.exe",
    "wscript.exe",
    "cscript.exe",
    "mshta.exe",
    "rundll32.exe",
    "regsvr32.exe",
    "bitsadmin.exe",
    "certutil.exe"
)
| project Timestamp, DeviceName, AccountName,
          InitiatingProcessFileName, InitiatingProcessCommandLine,
          FileName, ProcessCommandLine, SHA1
| order by Timestamp desc

This query is not a CVE-specific signature. It identifies suspicious process relationships that may indicate post-exploitation or abuse of browser-launched execution. Validate results against approved enterprise applications and browser extensions.

Endpoint teams can also review process creation logs for patterns such as:

ParentImage: *\chrome.exe
ChildImage: *\powershell.exe
CommandLine: *-enc*

or:

ParentImage: *\chrome.exe
ChildImage: *\mshta.exe

These patterns are investigation leads, not proof of CVE-2026-125347 exploitation. Correlate them with:

• The Chrome version.
• The initiating user.
• Browser history.
• DNS records.
• Proxy logs.
• Downloaded files.
• Subsequent persistence activity.
• Credential access or lateral-movement telemetry.

Network monitoring should look for unusual outbound connections made immediately after a victim visits an untrusted page, but defenders should not expect a stable IDS signature from the available information. TLS, content delivery networks, URL rotation, and legitimate hosting services can make network-only detection unreliable.

Remediation and Patching

The primary remediation is to update Google Chrome to 157.0.8103.50 or later. Use enterprise browser management, software distribution, or the organization’s endpoint-management platform rather than relying solely on users to select “About Chrome.”

After deployment, verify that the browser has restarted or otherwise loaded the patched executable. Downloading an update without completing the browser restart does not necessarily remove the vulnerable process from memory.

Until patching is complete:

• Reduce exposure to untrusted web content.
• Reinforce phishing-resistant authentication and user-reporting workflows.
• Restrict high-risk browsing from privileged administration workstations.
• Consider temporary web filtering for newly registered or suspicious domains.
• Prioritize patching on systems with access to sensitive data.

These measures reduce attack opportunity but do not correct the authorization flaw.

Because the supplied research does not identify a vendor-published configuration workaround, do not assume that disabling an arbitrary Chrome feature provides protection.

If an organization cannot update immediately, the safest temporary control is to prevent vulnerable Chrome installations from accessing untrusted content and to use a supported, fully updated browser approved by the organization, after confirming that the alternative is not affected by the same underlying code.

Linux Update Commands

On Debian-based systems, an administrator may update the Google Chrome stable package with:

sudo apt-get update
sudo apt-get install --only-upgrade google-chrome-stable
google-chrome --version

On RPM-based systems:

sudo dnf upgrade google-chrome-stable
google-chrome --version

Windows Version Verification

For Windows environments using an enterprise software-distribution tool, deploy the organization’s approved Chrome installer or package, then verify the resulting version remotely.

A conceptual PowerShell verification check is:

$minimum = [version]"157.0.8103.50"
$chrome = Get-Item "C:\Program Files\Google\Chrome\Application\chrome.exe" `
  -ErrorAction SilentlyContinue

if ($chrome) {
    $installed = [version]$chrome.VersionInfo.ProductVersion
    [pscustomobject]@{
        Computer = $env:COMPUTERNAME
        InstalledVersion = $installed
        Vulnerable = ($installed -lt $minimum)
    }
}

The path may differ for per-user installations or 32-bit deployments, so production inventory should account for those locations.

After updating, close all Chrome processes or restart the endpoint according to the organization’s change policy, then confirm that no older Chrome process remains.

For incident response, isolate endpoints showing suspicious Chrome-child-process activity, preserve browser and endpoint telemetry, and collect downloaded files and relevant memory or disk artifacts according to the response plan. Rotate credentials if post-exploitation access is suspected.

Do not wait for CISA KEV inclusion before taking these actions.

References

1. National Vulnerability Database, CVE-2026-125347
   Vulnerability record containing the description, CVSS score, affected product information, publication metadata, and references.
   https://nvd.nist.gov/vuln/detail/CVE-2026-125347

2. Google Chrome Releases, Stable Channel Update for Desktop
   Vendor release reference associated with the fixed Chrome version.
   https://chromereleases.googleblog.com/2026/11/stable-channel-update-for-desktop_018223192.html

3. Chromium Issue Tracker, Issue 561996724
   Upstream Chromium issue associated with the vulnerability.
   https://issues.chromium.org/issues/561996724

4. CISA Known Exploited Vulnerabilities Catalog
   The available lookup did not identify CVE-2026-125347 as listed at the time of checking.
   https://www.cisa.gov/known-exploited-vulnerabilities-catalog

5. CVE record status and source limitations
   The available NVD data did not provide a complete CVSS vector or implementation-level root-cause details. The Google Chrome Releases and Chromium issue pages could not be fully retrieved during research because of anti-automation or rate-limiting responses. Claims about public PoCs and active exploitation are therefore limited to the sources available at publication time.

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