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CVE-2026-87491

Actively Exploited Out-of-Bounds Write in Google Chrome V8

CISA: Google Chromium V8 Out of Bounds Write Vulnerability

CVSS 3.1
8.8 high
EPSS
4%p89
Published
·
Added to KEV
Analyze CVE-2026-87491 with Vani AIImpact, affected versions, exploitation status, mitigations and detection

CVE-2026-87491 is an out-of-bounds write (CWE-787) in the V8 JavaScript engine in Google Chrome, fixed in Chrome 153.0.8010.36, which Google shipped alongside roughly 230 other security fixes. An attacker can trigger the flaw remotely by luring a user (user interaction required) into opening a crafted HTML page that corrupts memory in V8. Successful exploitation allows the attacker to execute arbitrary code inside the Chrome browser sandbox, which constrains but does not eliminate the impact. All Google Chrome users running versions prior to 153.0.8010.36 are affected; because the flaw resides in V8, CISA tracks it as 'Google Chromium V8', and other Chromium-based browsers may inherit the fix in their own updates. The flaw is being actively exploited in the wild — it is the seventh actively exploited Chrome zero-day of 2026 and was added to CISA's KEV catalog on 2026-09-09 — though no public proof-of-concept is known and ransomware use is unknown.

What to do: Update Google Chrome to 153.0.8010.36 or later immediately (open Help > About Google Chrome to force the update and relaunch), and verify the version on all endpoints. Also patch headless or automated Chrome deployments (CI runners, scrapers, kiosks, CDP-based tooling) that may lag auto-updates, and prioritize remediation per CISA KEV and BOD 26-04 requirements for federal systems. No public PoC is known and ransomware use is unknown, but confirmed in-the-wild exploitation warrants urgent patching.

ProductAffected
Google Chrome (V8 JavaScript engine; tracked by CISA as 'Google Chromium V8')prior to 153.0.8010.36
Estimated exposure
massbillions of installations (Chrome's install base exceeds 3 billion users) — Chrome holds roughly two-thirds of global browser usage share with a multi-billion-user install base, so the number of potentially affected endpoints is in the billions, though rapid auto-updates shrink the persistently vulnerable window.

Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.

Description · NVD

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)

KEVCISA Known Exploited Vulnerability
Affected
Google Chromium V8
Required action
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.
Due date
Ransomware use
Unknown
Vendors
google
Products
chrome
Weakness
CWE-787
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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