Auth bypass in Google Chrome
CVE-2026-78953
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)
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 3.1 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.002 (10.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 11th percentile — 10.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.002 · change: -0.001
Affected products
Weakness classification (CWE)
References
- chromereleases.googleblog.com/2026/08/stable-channel-update-for-desktop_0256176… (Release Notes, Vendor Advisory)
- issues.chromium.org/issues/516665605 (Permissions Required)
Frequently asked questions
- What is CVE-2026-78953?
- CVE-2026-78953 is a low-severity vulnerability in Google Chrome, classified under Missing Authorization. CVSS score: 3.1/10. Published 2026-08-25.
- How severe is CVE-2026-78953?
- Low severity. CVSS v3 base score is 3.1 out of 10.