CVE-2026-40399
published 2026-05-12CVE-2026-40399: Concurrent execution using shared resource with improper synchronization ('race condition') in Windows TCP/IP allows an authorized attacker to elevate…
PriorityP347high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.33%
25.0th percentile
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows TCP/IP allows an authorized attacker to elevate privileges locally.
Affected
26 ranges· showing 25
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| microsoft | windows_10_1607 | < 10.0.14393.9140 | 10.0.14393.9140 |
| microsoft | windows_10_1809 | < 10.0.17763.8755 | 10.0.17763.8755 |
| microsoft | windows_10_21h2 | < 10.0.19044.7291 | 10.0.19044.7291 |
| microsoft | windows_10_22h2 | < 10.0.19045.7291 | 10.0.19045.7291 |
| microsoft | windows_10_version_1607 | >= 10.0.14393.0 < 10.0.14393.9140 | 10.0.14393.9140 |
| microsoft | windows_10_version_1809 | >= 10.0.17763.0 < 10.0.17763.8755 | 10.0.17763.8755 |
| microsoft | windows_10_version_21h2 | >= 10.0.19044.0 < 10.0.19044.7291 | 10.0.19044.7291 |
| microsoft | windows_10_version_22h2 | >= 10.0.19045.0 < 10.0.19045.7417 | 10.0.19045.7417 |
| microsoft | windows_11_23h2 | < 10.0.22631.7079 | 10.0.22631.7079 |
| microsoft | windows_11_24h2 | < 10.0.26100.8390 | 10.0.26100.8390 |
| microsoft | windows_11_25h2 | < 10.0.26200.8390 | 10.0.26200.8390 |
| microsoft | windows_11_26h1 | < 10.0.28000.2113 | 10.0.28000.2113 |
| microsoft | windows_11_version_23h2 | >= 10.0.22631.0 < 10.0.22631.7079 | 10.0.22631.7079 |
| microsoft | windows_11_version_23h2 | >= 10.0.22631.0 < 10.0.22631.7219 | 10.0.22631.7219 |
| microsoft | windows_11_version_24h2 | >= 10.0.26100.0 < 10.0.26100.8457 | 10.0.26100.8457 |
| microsoft | windows_11_version_25h2 | >= 10.0.26200.0 < 10.0.26200.8457 | 10.0.26200.8457 |
| microsoft | windows_11_version_26h1 | >= 10.0.28000.0 < 10.0.28000.2113 | 10.0.28000.2113 |
| microsoft | windows_server_2016 | < 10.0.14393.9140 | 10.0.14393.9140 |
| microsoft | windows_server_2016 | >= 10.0.14393.0 < 10.0.14393.9140 | 10.0.14393.9140 |
| microsoft | windows_server_2019 | < 10.0.17763.8755 | 10.0.17763.8755 |
| microsoft | windows_server_2019 | >= 10.0.17763.0 < 10.0.17763.8755 | 10.0.17763.8755 |
| microsoft | windows_server_2022 | < 10.0.20348.5074 | 10.0.20348.5074 |
| microsoft | windows_server_2022 | >= 10.0.20348.0 < 10.0.20348.5139 | 10.0.20348.5139 |
| microsoft | windows_server_2022_23h2 | < 10.0.25398.2330 | 10.0.25398.2330 |
| microsoft | windows_server_2025 | < 10.0.26100.32772 | 10.0.26100.32772 |
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VulDB
Microsoft Windows up to Server 2025 TCP/IP stack-based overflow
vuldb·2026-05-12
CVE-2026-40399 [CRITICAL] Microsoft Windows up to Server 2025 TCP/IP stack-based overflow
A vulnerability has been found in Microsoft Windows and classified as critical. This issue affects some unknown processing of the component TCPIP. The manipulation leads to stack-based buffer overflow.
This vulnerability is documented as CVE-2026-40399. The attack needs to be performed locally. There is not any exploit available.
The affected component should be upgraded.
GHSA
GHSA-jfvc-3h8q-fchp: Stack-based buffer overflow in Windows TCP/IP allows an authorized attacker to elevate privileges locally
ghsa_unreviewed·2026-05-12
CVE-2026-40399 [HIGH] CWE-121 GHSA-jfvc-3h8q-fchp: Stack-based buffer overflow in Windows TCP/IP allows an authorized attacker to elevate privileges locally
Stack-based buffer overflow in Windows TCP/IP allows an authorized attacker to elevate privileges locally.
No detection rules found.
No public exploits indexed.
Rapid7
Patch Tuesday - May 2026
blogs_rapid7·2026-05-13·CVSS 10.0
CVE-2026-41089 [CRITICAL] Patch Tuesday - May 2026
Microsoft is publishing 137 vulnerabilities on May 2026 Patch Tuesday . Microsoft is not aware of exploitation in the wild or public disclosure for any of these vulnerabilities. So far this month, Microsoft has provided patches to address 133 browser vulnerabilities, which are not included in the Patch Tuesday count above.
## Windows Netlogon: critical RCE
Anyone responsible for securing a domain controller should prioritize remediation of CVE-2026-41089 , which is a critical stack-based buffer overflow in Windows Netlogon with a CVSS v3 base score of 9.8. Exploitation leads to execution in the context of the Netlogon service, so that’s SYSTEM privileges on the domain controller. For most pentesters, that’s the point at which the customer report more or less writes itself. No privileges
Sans Isc
Microsoft May 2026 Patch Tuesday, (Tue, May 12th)
blogs_sans_isc·2026-05-12·CVSS 4.3
CVE-2026-41103 [MEDIUM] Microsoft May 2026 Patch Tuesday, (Tue, May 12th)
Microsoft May 2026 Patch Tuesday
Published: 2026-05-12. Last Updated: 2026-05-12 18:29:36 UTC
by Johannes Ullrich (Version: 1)
0 comment(s)
Today's Microsoft patch Tuesday fixes 137 different vulnerabilities. In addition, the update addresses 137 Chromium-related issues affecting Microsoft Edge.
There are no already disclosed or already exploited vulnerabilities included in today's patches. I removed the Chromium issues from the table below and included only the 137 Microsoft issues to make it more readable.
Note that issues related to Microsoft Azure are labeled as "no customer action required.
Significant Vulnerabilities of interest:
CVE-2026-41103: This vulnerability affects the Microsoft SSO Plugin for Jira & Confluence. Exploitation could lead to an elevation of privileges. Wit
2026-05-12
Published