Microsoft · Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component
Affects MicrosoftSource GCVE Database
Not known to be exploited · CVSS 9.6 Critical · patch available : patch Microsoft as a priority.
Data as of 14 Nov 2026, 09:02 UTC
- Patch
- Available
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Microsoft Security Response Center Microsoft | Affected
| Fixed in
|
Description
CVE-2026-8959 is a vulnerability in a Microsoft Win32 component called Widget, caused by incorrect boundary conditions that could allow a sandbox escape. This means that an attacker might bypass sandbox restrictions and execute code outside the intended isolated environment. The affected version is exactly 4.0. No CVSS score or detailed impact information is provided.