NPM · SEPTEMBER 2026 · EARLY WARNING

Google Chromium V8 Vulnerability: Critical Out-of-Bounds Write

EARLY WARNING · UNCONFIRMED. This page describes a developing threat that 0Day surfaced from early signals and has not yet independently confirmed. Details may change. Always verify against the primary sources before acting.
Severity
HIGH
Affected component
chromium v8 (npm)
Patched version
Not yet available
CVE-2026-87491

An out-of-bounds write vulnerability in Google Chromium V8 has been reported, which could allow remote attackers to execute arbitrary code inside the sandbox via a crafted HTML page. This vulnerability may affect multiple web browsers that utilize Chromium, including Google Chrome, Microsoft Edge, and Opera.

What happened

An out-of-bounds write vulnerability in Google Chromium V8, identified as CVE-2026-87491, has been reported to be exploited in the wild. This vulnerability allows a remote attacker to execute arbitrary code inside the sandbox via a specially crafted HTML page. The vulnerability affects multiple web browsers that utilize Chromium, including Google Chrome, Microsoft Edge, and Opera. Security researcher Jihyeon Jeong of Compsec Lab, Seoul National University, discovered and reported the flaw on August 6, 2026, and received a $2,500 bug bounty reward for responsible disclosure.

Google has acknowledged the existence of an exploit for CVE-2026-87491 in the wild but has not disclosed specific details about the attacks or the attackers. The company has released updates to address the vulnerability, but the exact version range affected has not been published. Users are advised to monitor for patches and upgrade Chromium V8 to the latest version once available.

What to do about it

How 0Day would have caught this

MATCHED TO YOUR ACTUAL DEPENDENCY GRAPH0Day matches every incoming threat signal against your GitHub organization’s full dependency graph, including transitive dependencies. If chromium v8 is anywhere in your dependency tree, the engineers who own the affected repositories get a push alert the moment it is flagged — no manual audit to remember to run.

Read how this differs from waiting on a scanner to catch a known advisory, or see the exact, read-only access 0Day needs to do this for an organization.

Frequently asked questions

Am I affected?

If you are using web browsers that utilize Chromium, including Google Chrome, Microsoft Edge, and Opera, you may be affected by this vulnerability.

What should I do right now?

Monitor for patches and upgrade Chromium V8 to the latest version once available. Stay informed by consulting primary sources for updates on the vulnerability and any patches released.

Has this been exploited in the wild?

Yes, the vulnerability has been reported to be exploited in the wild.

Sources

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