Description
Double free in Windows Message Queuing allows an authorized attacker to elevate privileges locally.
Published: 2026-05-12
Score: 7.8 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

The vulnerability arises from a double free bug in the Windows Message Queuing (MSMQ) component, a flaw under CWE‑415 that allows an authorized user to corrupt memory and bypass privilege checks, thereby enabling local privilege escalation. Because MSMQ runs with system-level privileges, exploitation can grant the attacker full control over the affected machine.

Affected Systems

Microsoft Windows client and server editions are impacted. This includes Windows 10 build 1607, 1809, 21H2, and 22H2; Windows 11 builds 23H2, 24H2, 25H2, 26H1, and 22H3; and Windows Server releases 2012, 2012 R2, 2016, 2016 (Server Core installation), 2019, 2019 (Server Core installation), 2022, 23H2 Edition (Server Core installation), 2025, and 2025 (Server Core installation).

Risk and Exploitability

The CVSS score of 7.8 denotes a high-risk vulnerability. With no EPSS value available, the likelihood of exploitation is uncertain, but the flaw is not listed in CISA’s KEV catalog. The attack requires local, authorized access, and an attacker who can act with the MSMQ service can use the double‑free defect to gain SYSTEM privileges, allowing arbitrary code execution and total control over the operating system.

Generated by OpenCVE AI on May 12, 2026 at 19:17 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Download and install the MSMQ security update from Microsoft’s update guide (https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-33838).
  • If the Message Queuing service is not required, disable or uninstall it to eliminate the attack surface.
  • Apply the principle of least privilege by restricting local user access to MSMQ and ensuring only administrators can interact with the service until the update is applied.

Generated by OpenCVE AI on May 12, 2026 at 19:17 UTC.

Tracking

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Advisories

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History

Tue, 12 May 2026 17:30:00 +0000

Type Values Removed Values Added
Description Double free in Windows Message Queuing allows an authorized attacker to elevate privileges locally.
Title Windows Message Queuing (MSMQ) Elevation of Privilege Vulnerability
First Time appeared Microsoft
Microsoft windows 10 1607
Microsoft windows 10 1809
Microsoft windows 10 21h2
Microsoft windows 10 22h2
Microsoft windows 11 23h2
Microsoft windows 11 24h2
Microsoft windows 11 25h2
Microsoft windows 11 26h1
Microsoft windows Server 2012
Microsoft windows Server 2012 R2
Microsoft windows Server 2016
Microsoft windows Server 2019
Microsoft windows Server 2022
Microsoft windows Server 2025
Microsoft windows Server 23h2
Weaknesses CWE-415
CPEs cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_21H2:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_22H2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_23H2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_23H2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_24H2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_25H2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_26H1:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2012:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2012_R2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_23h2:*:*:*:*:*:*:*:*
Vendors & Products Microsoft
Microsoft windows 10 1607
Microsoft windows 10 1809
Microsoft windows 10 21h2
Microsoft windows 10 22h2
Microsoft windows 11 23h2
Microsoft windows 11 24h2
Microsoft windows 11 25h2
Microsoft windows 11 26h1
Microsoft windows Server 2012
Microsoft windows Server 2012 R2
Microsoft windows Server 2016
Microsoft windows Server 2019
Microsoft windows Server 2022
Microsoft windows Server 2025
Microsoft windows Server 23h2
References
Metrics cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C'}

Subscriptions

Microsoft Windows 10 1607 Windows 10 1809 Windows 10 21h2 Windows 10 22h2 Windows 11 23h2 Windows 11 24h2 Windows 11 25h2 Windows 11 26h1 Windows Server 2012 Windows Server 2012 R2 Windows Server 2016 Windows Server 2019 Windows Server 2022 Windows Server 2025 Windows Server 23h2
cve-icon MITRE

Status: PUBLISHED

Assigner: microsoft

Published:

Updated: 2026-05-12T17:54:10.120Z

Reserved: 2026-03-24T00:52:01.353Z

Link: CVE-2026-33838

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-12T18:17:05.820

Modified: 2026-05-12T18:17:05.820

Link: CVE-2026-33838

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-12T19:30:23Z

Weaknesses