CVE intelligenceCISA KEV

CVE-2026-87491

Google Chromium V8 Out of Bounds Write Vulnerability

Published Sep 9, 2026Sources checked Nov 8, 2026

8.8HIGHCVSS out of 10

What this means

Actively exploited

CISA lists CVE-2026-87491 in its Known Exploited Vulnerabilities catalog, which means exploitation has been observed. The entry applies to Google Chromium V8.

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Sep 11, 2026

Release Notes

Vendor-listed releases

153.0.4234.32

CISA KEVListedObserved exploitation

EPSS3.5%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors1Source-linked actor relationships

Overview

What is CVE-2026-87491?

Out of bounds write in V8 in Google Chrome prior to 153.0.8010.36 allowed a remote attacker to execute arbitrary code inside the sandbox via a crafted HTML page. (Chromium security severity: Medium)

Source: NVD

CISA says:Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.CISA catalog due date Sep 23, 2026