CVE-2026-9966Network attack vector

Sandbox escape via XML integer overflow

Published May 28, 2026 · Updated May 28, 2026

Integer overflow in XML in Google Chrome before 148.0.7778.216 on Windows allows remote attackers to escape the sandbox via crafted HTML. Google has not disclosed the affected XML routine, the overflowing arithmetic operation, or how the resulting state crosses the sandbox boundary. Exploitation requires user interaction with crafted HTML and prior compromise of the renderer process; success escapes that renderer sandbox.

CVSS severity8.3
High
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer overflow in XML in Google Chrome before 148.0.7778.216 on Windows allows remote attackers to escape the sandbox via crafted HTML. Google has not disclosed the affected XML routine, the overflowing arithmetic operation, or how the resulting state crosses the sandbox boundary. Exploitation requires user interaction with crafted HTML and prior compromise of the renderer process; success escapes that renderer sandbox.

The record

CVE
CVE-2026-9966
Published
May 28, 2026
Updated
May 28, 2026
Vendor
Go standard library
Product
Google Chrome
Classifications
CWE-472, T1068
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 28, 2026CVE publishedPublication date reported by the CVE source.
  2. May 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=148.0.7778.216 <148.0.7778.216

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Go standard library · Google Chromeversion=148.0.7778.216 <148.0.7778.216

Published CVSS scores

8.3CISA-ADPCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-472External Control of Assumed-Immutable Web Parameter
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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