Windows Hyper-V Elevation of Privilege Vulnerability
Assessment
Double free in Windows Hyper-V allows an authorized attacker to elevate privileges locally.
- Severity
- Important
- CVSS base score
- 7.8CVSS:3.1/
AV:L/ AC:L/ PR:L/ UI:N/ S:U/ C:H/ I:H/ A:H/ E:U/ RL:O/ RC:C - Impact
- Elevation of Privilege
- EPSS, next 30 days
- 0.3%Higher than 23.8% of scored CVEs · FIRST model run 25 Oct 2026 · about EPSS
- Public exploit code
- No Nuclei template lists it
- Exploitability
- Exploitation Less Likely
- Publicly disclosed
- No
- Customer action
- Required: apply the update
- Component
- Windows Hyper-V
- Weakness
- CWE-415: Double Free
- Issued by
- Microsoft
- Published
- 13 Oct 2026 · October 2026
- Last revised
- 13 Oct 2026
CVSS 3.1 base metricsRed raises the risk · green lowers it
- Attack vector
- LocalAV:L
- Attack complexity
- LowAC:L
- Privileges required
- LowPR:L
- User interaction
- NoneUI:N
- Scope
- UnchangedS:U
- Confidentiality
- HighC:H
- Integrity
- HighI:H
- Availability
- HighA:H
Updates that fix it
4 KBs| KB | Type | Restart | Applies to | Known issues | Other CVEs |
|---|---|---|---|---|---|
| KB5126646 | Security Update | Required | Windows Server 2025, Windows Server 2025 (Server Core installation) | MitigatedUsers might be unable to sign in to OWA or send emails on Exchange Server | All CVEs in KB5126646 |
| KB5126653 | Security Update | Required | Windows 11 Version 23H2 for ARM64-based Systems, Windows 11 Version 23H2 for x64-based Systems | None listed | All CVEs in KB5126653 |
| KB5126655 | Security Update | Required | Windows Server 2022, Windows Server 2022 (Server Core installation) | MitigatedUsers might be unable to sign in to OWA or send emails on Exchange Server | All CVEs in KB5126655 |
| KB5127648 | Security Update | Required | Windows 11 Version 24H2 for ARM64-based Systems, Windows 11 Version 24H2 for x64-based Systems, Windows 11 Version 25H2 for ARM64-based Systems and 3 more | None listed | All CVEs in KB5127648 |
Affected products
Windows12 affected products
- Windows 11 Version 23H2 for ARM64-based Systems
- Windows 11 Version 23H2 for x64-based Systems
- Windows 11 Version 24H2 for ARM64-based Systems
- Windows 11 Version 24H2 for x64-based Systems
- Windows 11 Version 25H2 for ARM64-based Systems
- Windows 11 Version 25H2 for x64-based Systems
- Windows 11 Version 26H2 for ARM64-based Systems
- Windows 11 Version 26H2 for x64-based Systems
- Windows Server 2022
- Windows Server 2022 (Server Core installation)
- Windows Server 2025
- Windows Server 2025 (Server Core installation)
What changed
First observed 14 Oct 2026- 25 Oct 2026 · 17:12:51 UTC EPSS0.3%; scored 24 Oct 2026 → 0.3%; scored 25 Oct 2026
- 25 Oct 2026 · 01:34:18 UTC EPSS0.3%; scored 23 Oct 2026 → 0.3%; scored 24 Oct 2026
- 23 Oct 2026 · 15:51:28 UTC EPSS0.3%; scored 22 Oct 2026 → 0.3%; scored 23 Oct 2026
- 23 Oct 2026 · 09:33:49 UTC Public exploit codeUnknown: exploit-code evidence is incomplete or retained → No Nuclei template listed
- 23 Oct 2026 · 09:33:49 UTC CISA KEVUnknown: catalog evidence is incomplete or retained → Not listed in the collected catalog
- 23 Oct 2026 · 09:33:49 UTC Source coverage: public-exploit-codeIncomplete → Current
- 23 Oct 2026 · 09:33:49 UTC Source coverage: first-epssIncomplete → Current
- 23 Oct 2026 · 09:33:49 UTC Source coverage: cisa-kevIncomplete → Current
- 23 Oct 2026 · 09:33:49 UTC Source coverage: msrc-cvrfIncomplete → Current
- 23 Oct 2026 · 08:31:50 UTC Public exploit codeNo Nuclei template listed → Unknown: exploit-code evidence is incomplete or retained
- 23 Oct 2026 · 08:31:50 UTC CISA KEVNot listed in the collected catalog → Unknown: catalog evidence is incomplete or retained
- 23 Oct 2026 · 08:31:50 UTC Source coverage: public-exploit-codeCurrent → Incomplete
Show 12 more recent changes
- 23 Oct 2026 · 08:31:50 UTCSource coverage: first-epss Current → Incomplete
- 23 Oct 2026 · 08:31:50 UTCSource coverage: cisa-kev Current → Incomplete
- 23 Oct 2026 · 08:31:50 UTCSource coverage: msrc-cvrf Current → Incomplete
- 22 Oct 2026 · 17:33:15 UTCEPSS 0.3%; scored 21 Oct 2026 → 0.3%; scored 22 Oct 2026
- 21 Oct 2026 · 21:47:24 UTCEPSS 0.3%; scored 20 Oct 2026 → 0.3%; scored 21 Oct 2026
- 20 Oct 2026 · 20:53:31 UTCEPSS 0.3%; scored 19 Oct 2026 → 0.3%; scored 20 Oct 2026
- 19 Oct 2026 · 15:12:40 UTCEPSS 0.3%; scored 18 Oct 2026 → 0.3%; scored 19 Oct 2026
- 18 Oct 2026 · 14:54:30 UTCEPSS 0.3%; scored 16 Oct 2026 → 0.3%; scored 18 Oct 2026
- 18 Oct 2026 · 14:54:30 UTCLink: October 2026 → /security?release=2026-Oct#cves
- 16 Oct 2026 · 16:13:25 UTCEPSS 0.3%; scored 15 Oct 2026 → 0.3%; scored 16 Oct 2026
- 15 Oct 2026 · 21:30:54 UTCEPSS 0.3%; scored 14 Oct 2026 → 0.3%; scored 15 Oct 2026
- 15 Oct 2026 · 01:07:54 UTCEPSS Not scored → 0.3%; scored 14 Oct 2026
The most recent 100 field changes are listed. Complete recorded revisions are kept separately.
Cite this recorded revision to keep the same title, summary, facts and links when the page changes.
A day selects the latest observation by the end of that UTC day; today's selection can change until midnight. History starts when this installation records it.
Explore global source statements, affected packages and advisory history for CVE-2026-88071. The catalog has a separate collection scope from Microsoft release records.
Explicit identifiers and source references
These records connect through source-stated identifiers. Shared identifiers or dates alone do not establish shared exposure, root cause or applicability.
CVE-2026-88071 · Microsoft / collected KEV context
cve-program · CVE-2026-88071
Related operational evidence
Explicit CVE identifiers- Windows Hyper-V Elevation of Privilege Vulnerability · Published vulnerability · 13 Oct 2026