CVE-2026-78903: chrome — Fix

Description

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)

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CVSS v3.1 Score

3.1

LOW

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N

EPSS — Exploit Prediction

0.0027

Probability of exploitation

0.19%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-459 CWE-459

Affected Products

Vendor	Product	Versions
google	chrome	< 152.0.7977.65

References

Advisories & Patches

https://chromereleases.googleblog.com/2026/08/stable-channel-update-for-desktop_0256176589.html

Other References

https://issues.chromium.org/issues/518078552

Frequently Asked Questions

What is CVE-2026-78903? +

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) It has a CVSS v3.1 base score of 3.1 (LOW).

How severe is CVE-2026-78903? +

CVE-2026-78903 has a CVSS v3.1 score of 3.1 out of 10, rated LOW. This is a low-severity vulnerability with limited impact. The EPSS score is 0.0027, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-78903? +

CVE-2026-78903 affects products from google, specifically: chrome. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-78903? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-78903