CVE-2026-12437Network attack vector

Sandbox escape via WebShare use-after-free

Published Jun 17, 2026 · Updated Jun 17, 2026

Use-after-free in WebShare in Google Chrome before 149.0.7827.155 on Windows allows remote attackers to escape the browser sandbox. WebShare accesses an object after its memory has been freed, but Google has not disclosed the triggering lifetime error or code locus. Exploitation requires a crafted HTML page and prior renderer compromise; success escapes the sandbox and exposes the Windows host.

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

What happened

Use-after-free in WebShare in Google Chrome before 149.0.7827.155 on Windows allows remote attackers to escape the browser sandbox. WebShare accesses an object after its memory has been freed, but Google has not disclosed the triggering lifetime error or code locus. Exploitation requires a crafted HTML page and prior renderer compromise; success escapes the sandbox and exposes the Windows host.

The record

CVE
CVE-2026-12437
Published
Jun 17, 2026
Updated
Jun 17, 2026
Vendor
Go standard library
Product
Google Chrome
Classifications
CWE-416, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 17, 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=149.0.7827.155 <149.0.7827.155

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Go standard library · Google Chromeversion=149.0.7827.155 <149.0.7827.155

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-416Use After Free
T1203Exploitation for Client Execution

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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