CVE-2026-9938: Inappropriate implementation in V8 in Google Chrome prior to 148

Synopsis

An inappropriate implementation flaw in the V8 JavaScript engine affects Google Chrome versions prior to 148.0.7778.216. The vulnerability is reachable over the network and requires no authentication, though the victim must visit a crafted HTML page for the exploit to trigger. Successful exploitation gives a remote attacker arbitrary code execution inside the Chrome sandbox. A patched-image rebuild at version 148.0.7778.216 is available on HarborGuard for environments running an affected version.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

  The attacker delivers the exploit over the network by luring the victim to a crafted HTML page, requiring the Chrome instance to have outbound or inbound web access.

• AuthenticationNot required

  No credentials or account are needed; any unauthenticated visitor to the attacker-controlled page is a viable target.

• Victim interactionRequired

  The victim must actively visit or be redirected to the crafted HTML page, making social engineering or malicious ad delivery the primary delivery mechanism.

• Attack complexityDetail

  Attack complexity is low, meaning the exploit is reliable and does not depend on race conditions, specific memory layouts, or other environmental factors.

Blast Radius

• A successful attacker executes arbitrary code within the Chrome renderer sandbox, gaining control of the JavaScript execution environment for that browsing context.
• Confidentiality impact is high: the attacker reads data accessible to the renderer, including page content, stored credentials surfaced by autofill, and session tokens held in memory.
• Integrity impact is high: the attacker modifies in-page data and can interact with web APIs to alter persisted state such as IndexedDB records or cached service-worker scripts.
• Availability impact is high: the attacker crashes or hangs the affected renderer process, disrupting the user's session and any dependent background workers.