EUVD-2026-34673
GHSA-3cxh-6mgp-qvhv
Severity by source
AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
Primary rating from Vendor (google).
CVSS VectorVendor: google
Lifecycle Timeline
4DescriptionCVE.org
Insufficient policy enforcement in DevTools in Google Chrome prior to 149.0.7827.53 allowed an attacker who convinced a user to install a malicious extension to leak cross-origin data via a crafted Chrome Extension. (Chromium security severity: Medium)
AnalysisAI
Cross-origin data leakage in Google Chrome's DevTools component (prior to 149.0.7827.53) enables an attacker to bypass same-origin policy enforcement through a crafted malicious extension. Exploitation requires convincing a target user to install the attacker-controlled extension, after which cross-origin data can be exfiltrated via insufficient DevTools policy controls. No public exploit code has been identified at time of analysis, and the EPSS score of 0.01% (1st percentile) indicates very low observed exploitation probability; the vulnerability is not listed in the CISA KEV catalog.
Technical ContextAI
The vulnerability resides in Chromium's DevTools subsystem and is rooted in CWE-284 (Improper Access Control) - specifically, insufficient policy enforcement that governs how Chrome Extensions interact with DevTools when accessing cross-origin resources. Chrome Extensions operate within a privileged but sandboxed context; DevTools APIs expose powerful inspection capabilities that, when insufficiently gated, can allow extension scripts to read data from origins other than the extension's own. The CVSS vector (AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N) confirms the vulnerability is network-reachable with low attack complexity, no required privileges, but necessitates user interaction (UI:R) - consistent with the social engineering step of extension installation. The scope is unchanged (S:U), meaning the breach is contained to the browser's security context rather than escaping to the underlying OS.
RemediationAI
The primary fix is upgrading to Google Chrome 149.0.7827.53 or later, which is confirmed available via the vendor's stable channel advisory (https://chromereleases.googleblog.com/2026/06/stable-channel-update-for-desktop.html). Chrome's automatic update mechanism will deliver this patch to most users without manual intervention; administrators managing enterprise fleets should verify deployment via Google Admin Console or endpoint management tooling. As a compensating control where immediate patching is not feasible, organizations can enforce enterprise extension policies to block installation of extensions not explicitly allowlisted via the ExtensionInstallAllowlist policy - this directly neutralizes the attack's required social engineering vector with no meaningful usability trade-off for managed users. Restricting Chrome DevTools access via the DeveloperToolsAvailability enterprise policy (set to '2' to disallow) would also block the exploitation path, though this may impact developer workflows. Neither workaround should substitute for patching.
Same weakness CWE-284 – Improper Access Control
View allSame technique Authentication Bypass
View allVendor StatusVendor
SUSE
Severity: Medium| Product | Status |
|---|---|
| openSUSE Tumbleweed | Fixed |
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External POC / Exploit Code
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