CVE-2026-9986
Description
Insufficient validation of untrusted input in OptimizationGuide in Google Chrome prior to 148.0.7778.216 allowed a remote attacker who had compromised the renderer process to perform UI spoofing via a crafted HTML page. (Chromium security severity: High)
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Immediate action: Deploy Chrome 148.0.7778.216 or later. For air-gapped or staging environments, disable OptimizationGuide as interim control:
Windows (GPO):
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome\OptimizationGuideServiceURL
Value: (empty string)macOS/Linux (managed policy JSON):
{
"OptimizationGuideServiceURL": "",
"ComponentUpdatesEnabled": true
}Test in isolated environment first—some users report slower page loads without optimization hints. Rollback: remove policy keys and restart Chrome.
Detection: Monitor Chrome crash logs for optimization_guide stack traces; abnormal dialog rendering may indicate exploitation attempts.
OS impact
Debian Mixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 148.0.7778.215-1~deb13u1 |
| sid | Fixed | 148.0.7778.215-1 |
| forky | Affected | — |
| bullseye | Affected | — |
| bookworm | Fixed | 148.0.7778.215-1~deb12u1 |
Linux kernel Fixed 1 release
| Version | Status | Fixed in |
|---|---|---|
| - | Not affected | — |
macOS Fixed 1 release
| Version | Status | Fixed in |
|---|---|---|
| - | Not affected | — |
References
CWEs
CWE-20
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.