CVE-2026-78903: Incomplete cleanup in SiteIsolation

Published May 30, 2026
·
Updated

Chromium: CVE-2026-78903 Incomplete cleanup in SiteIsolation

Other sources

Incomplete cleanup in SiteIsolation in Google Chrome prior to 152.0.7977.65 allowed a remote attacker who had compromised the renderer process to bypass site isolation via a crafted HTML page. (Chromium security severity: Medium)

— MITRE

This CVE was assigned by Chrome. Microsoft Edge (Chromium-based) ingests Chromium, which addresses this vulnerability. Please see Google Chrome Releases for more information.

— Microsoft

Credit

Google

Affected Software

5 affected componentsFixes available
Google Google Chrome<152.0.7977.65
Google Chrome<152.0.7977.64
152.0.7977.64
Google Chrome<152.0.7977.65
Microsoft Edge<152.0.4191.53
Microsoft Edge (Chromium-based)<152.0.4191.53
152.0.4191.53

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 152.0.7977.64
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 152.0.4191.53
  3. Upgrade

    Upgrade Chromium/Google Chrome (SiteIsolation) to a version that resolves this vulnerability.

    Fixed in 152.0.7977.65

Event History

May 30, 2026
CVE Published
12:00 AM
Data Sourced
12:00 AM
SeverityWeaknessAffected Software
Aug 25, 2026
CVE Published
via MITRE·08:10 PM
Data Sourced
via MITRE·08:10 PM
DescriptionWeakness
Data Sourced
via NVD·09:17 PM
DescriptionSeverityWeaknessAffected Software
Aug 28, 2026
Data Sourced
via Microsoft·02:00 PM
DescriptionSeverityWeaknessAffected Software
Updated
via Microsoft·02:00 PM
DescriptionAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

1

What must an attacker achieve before this issue can be exploited?

The attacker must first compromise the Chrome renderer process. The site-isolation bypass is then triggered using a crafted HTML page.

2

Which Chrome versions need to be remediated?

Google Chrome versions prior to 152.0.7977.65 are affected. Updating to 152.0.7977.65 or later addresses the affected version range described.

3

Is this a standalone remote compromise vulnerability?

No. The available information describes this as a post-renderer-compromise issue: it enables bypass of site isolation after the renderer process has already been compromised.

Company

Resources

Contact

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