CVE-2026-78953 Missing authorization in Chrome

What is CVE-2026-78953?

CVE-2026-78953 is a low-severity missing authorization vulnerability in Google Chrome, published on 25 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

Missing authorization 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 PDF file. (Chromium security severity: Medium)

Weakness: CWE-862

Which versions are affected by CVE-2026-78953?

It affects 1 product.

Products include Google Chrome.

How do I fix CVE-2026-78953?

Upgrade to a fixed version.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2026-78953 being exploited?

There is no known exploitation of CVE-2026-78953 in the wild and no public exploit code.

Other vulnerabilities in Google Chrome

• CVE-2022-4135 Google Chromium GPU Heap Buffer Overflow Exploited Critical 9.6
• CVE-2020-16017 Google Chrome Use-After-Free Exploited Critical 9.6
• CVE-2020-16010 Google Chrome for Android UI Heap Buffer Overflow Exploited Critical 9.6
• CVE-2026-87491 Google Chromium V8 Out of Bounds Write Exploited High 8.8
• CVE-2026-85046 Google Chromium V8 Type Confusion Exploited High 8.8

All Google Chrome vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2026-78953, ECHO-52ad-9b53-5ad8, GHSA-qwmc-fc5p-qxxh, MINI-9hhw-r5g3-pvcw.