Incomplete cleanup in Google Chromium - CVE-2026-78903

Vulnerability identifier: #VU145606

CSH Severity: Medium

CVSS v4: 5.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-78903

CWE-ID: CWE-459

Exploitation vector: Remote access

Exploit availability: Public exploit is available

The vulnerability allows a remote attacker to bypass site isolation protections.

The vulnerability exists due to incomplete cleanup in SiteIsolation when rendering content. A remote attacker can trigger the vulnerable behavior to bypass site isolation protections.

User interaction is required.

Google Chromium
Microsoft Edge
Google Chrome
Debian Linux
Fedora
chromium
chromium (Debian package)

Install security update from vendor's website.

Google Chromium - update to 152.0.7977.64
Microsoft Edge - update to 152.0.4191.53
Google Chrome - addressed in versions 151.0.7922.175, 152.0.7977.64
chromium - addressed in versions 152.0.7977.75-1.el9, 152.0.7977.75-1.el10_2, 152.0.7977.75-1.el10_3, 152.0.7977.75-1.el10_4, 152.0.7977.75-1.fc43, 152.0.7977.75-1.fc44, 152.0.7977.75-1.fc45
chromium (Debian package) - update to 152.0.7977.75-1~deb13u1

• Exploit #12987 - CVE-2026-78903-SWIFT-Kick-to-the-Creds (Offensive Research & Exploit Development. Vulnerability research, PoC development, and offensive tooling for financial infrastructure.) (August 31, 2026)

• https://chromereleases.googleblog.com/2026/08/stable-channel-update-for-desktop_0256176589.html
• https://crbug.com/518078552

• Multiple vulnerabilities in Google Chrome
• Multiple vulnerabilities in Microsoft Edge
• Debian update for chromium
• Fedora 45 update for chromium
• Fedora EPEL 10.4 update for chromium
• Fedora EPEL 9 update for chromium
• Fedora 43 update for chromium
• Fedora 44 update for chromium
• Fedora EPEL 10.2 update for chromium
• Fedora EPEL 10.3 update for chromium