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MSRC compact vulnerability detail

CVE-2026-40413 · Windows TCP/IP Denial of Service Vulnerability

Null pointer dereference in Windows TCP/IP allows an unauthorized attacker to deny service over an adjacent network.

Severity
Important
Impact
Denial of Service
CVSS
7.4 base · 6.4 temporal
Release
2026-05-12
Signals
Windows TCP/IP Denial of Service Exploited: No Publicly disclosed: No Exploitability: Exploitation Less Likely
CWE
CWE-476: NULL Pointer Dereference
Patch Diff
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Description
Null pointer dereference in Windows TCP/IP allows an unauthorized attacker to deny service over an adjacent network.
FAQ / Articles
FAQ
According to the CVSS metric, a successful exploitation could lead to a scope change (S:C). What does this mean for this vulnerability? In this case, a successful attack could be performed from a low privilege Hyper-V guest. The attacker could traverse the guest's security boundary to cause denial of service on the Hyper-V host environment.
FAQ
According to the CVSS score, the attack vector is adjacent (AV:A). What does this mean for this vulnerability? This attack is limited to systems connected to the same network segment as the attacker. The attack cannot be performed across multiple networks (for example, a WAN) and would be limited to systems on the same network switch or virtual network.