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AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Primary rating from Vendor (google).
CVSS VectorVendor: google
Lifecycle Timeline
4DescriptionCVE.org
Inappropriate implementation in Fenced Frames in Google Chrome prior to 149.0.7827.53 allowed a remote attacker who had compromised the renderer process to bypass site isolation via a crafted HTML page. (Chromium security severity: Low)
AnalysisAI
Site isolation bypass in Google Chrome's Fenced Frames component allows an attacker who has already compromised the renderer process to cross origin boundaries via a crafted HTML page. Affected versions are all Chrome releases prior to 149.0.7827.53 on desktop platforms. No public exploit code has been identified at time of analysis, and EPSS sits at a low 0.02% (4th percentile), consistent with Chromium's own 'Low' severity rating despite the 6.5 CVSS score - real-world risk is contingent on a separate, preceding renderer exploit.
Technical ContextAI
Fenced Frames is a Privacy Sandbox HTML primitive introduced in Chrome that embeds cross-site content without allowing bidirectional communication between the embedder and the framed content, serving as a site isolation enforcement boundary. CWE-346 (Origin Validation Error) identifies the root cause: the Fenced Frames implementation does not correctly validate origin or isolation context, allowing a malicious renderer to subvert the cross-site boundary guarantees the feature is designed to enforce. The affected component is the Blink rendering engine's Fenced Frames implementation (tracked in Chromium issue 487564032). CPE-implied scope covers Google Chrome for desktop (Windows, macOS, Linux) on all channels prior to stable version 149.0.7827.53.
RemediationAI
Update Google Chrome to version 149.0.7827.53 or later; this is the vendor-confirmed patched release documented at https://chromereleases.googleblog.com/2026/06/stable-channel-update-for-desktop.html. Chrome's auto-update mechanism will deliver this for most users, but enterprise environments managing Chrome via policy should verify deployment via chrome://settings/help or fleet management tooling. Because exploitation requires prior renderer compromise, organizations that enforce Chrome's Site Isolation policy (--site-per-process, enabled by default since Chrome 67) and keep renderer sandboxing enabled gain defense-in-depth even before patching. Disabling Fenced Frames via enterprise policy is a potential workaround but may break Privacy Sandbox features and is not formally recommended by Google as a mitigation for this issue.
Same weakness CWE-346 – Origin Validation Error
View allSame technique Authentication Bypass
View allVendor StatusVendor
SUSE
Severity: Medium| Product | Status |
|---|---|
| openSUSE Tumbleweed | Fixed |
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-34678
GHSA-w88q-hw69-7rhh