CVE-2026-9986: High Insufficient validation of untrusted input in OptimizationGuide

Published May 14, 2026
·
Updated

Chromium: CVE-2026-9986 Insufficient validation of untrusted input in OptimizationGuide

Other sources

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)

NVD

This CVE was assigned by Chrome. Microsoft Edge (Chromium-based) ingests Chromium, which addresses this vulnerability. Please see Google Chrome Releases for more information.

Microsoft

Credit

Google

Affected Software

8 affected componentsFixes available
Google Google Chrome<148.0.7778.216
Microsoft Edge (Chromium-based)
Microsoft Edge<148.0.3967.96
All of the following
Google Chrome<148.0.7778.216
Microsoft Windows
All of the following
Google Chrome<148.0.7778.215
Any of the following
Apple macOS
Linux Linux kernel

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade Chromium / Google Chrome to a version that resolves this vulnerability.

    Fixed in 148.0.7778.216
  2. Upgrade

    Upgrade Microsoft Edge (Chromium-based) to a version that resolves this vulnerability.

    Fixed in 148.0.7778.216

Event History

May 28, 2026
CVE Published
via MITRE·10:25 PM
Data Sourced
via MITRE·10:25 PM
DescriptionWeakness
Data Sourced
via NVD·11:16 PM
DescriptionSeverityWeaknessAffected Software
May 29, 2026
Data Sourced
via Microsoft·11:21 PM
DescriptionSeverityWeaknessAffected Software
Updated
via Microsoft·11:21 PM
DescriptionAffected Software
Jul 28, 2026
Data Sourced
12:00 AM
SeverityWeakness

Parent advisories

This vulnerability appears in the following advisories.

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Frequently Asked Questions

1

What is the severity of CVE-2026-9986?

CVE-2026-9986 has a medium severity rating of 4.2 according to the CVSS 3.1 system.

2

How do I fix CVE-2026-9986?

To fix CVE-2026-9986, update Google Chrome or Microsoft Edge to the latest version available, specifically version 148.0.7778.216 or later.

3

What impact does CVE-2026-9986 have on my system?

CVE-2026-9986 can allow remote attackers to perform UI spoofing, potentially misleading users with untrusted content.

4

Which software is affected by CVE-2026-9986?

CVE-2026-9986 affects Google Chrome prior to version 148.0.7778.216 and Microsoft Edge browsers that are based on Chromium.

5

What is the nature of CVE-2026-9986?

CVE-2026-9986 involves insufficient validation of untrusted input in the OptimizationGuide component of affected browsers.

Contact

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