CVE-2026-40406
published 2026-05-12CVE-2026-40406: Use after free in Windows TCP/IP allows an unauthorized attacker to disclose information over a network.
PriorityP349high7.5CVSS 3.1
AVNACLPRNUINSUCHINAN
EPSS
0.93%
56.6th percentile
Use after free in Windows TCP/IP allows an unauthorized attacker to disclose information over a network.
Affected
29 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_2012 | — | — |
| microsoft | windows_server_2012 | >= 6.2.9200.0 < 6.2.9200.26079 | 6.2.9200.26079 |
| microsoft | windows_server_2012_r2 | >= 6.3.9600.0 < 6.3.9600.23181 | 6.3.9600.23181 |
| 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 |
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GHSA
GHSA-37x6-37vf-qf3r: Use after free in Windows TCP/IP allows an unauthorized attacker to disclose information over a network
ghsa_unreviewed·2026-05-12
CVE-2026-40406 [HIGH] CWE-416 GHSA-37x6-37vf-qf3r: Use after free in Windows TCP/IP allows an unauthorized attacker to disclose information over a network
Use after free in Windows TCP/IP allows an unauthorized attacker to disclose information over a network.
VulDB
Microsoft Windows up to Server 2025 TCP/IP use after free
vuldb·2026-05-12
CVE-2026-40406 [LOW] Microsoft Windows up to Server 2025 TCP/IP use after free
A vulnerability categorized as problematic has been discovered in Microsoft Windows. This impacts an unknown function of the component TCPIP. Executing a manipulation can lead to use after free.
This vulnerability is handled as CVE-2026-40406. The attack can be executed remotely. There is not any exploit available.
It is advisable to upgrade the affected component.
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