CVE-2026-56181

HIGH

Origin validation error in Windows Network Address Translation (NAT) allows an unauthorized attacker to perform spoofing over an adjacent network.

CVSS v3.1 Score

8.3
HIGH
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Attack Vector
ADJACENT_NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Published: 7/14/2026Modified: 7/22/2026

Related Intelligence (2)

CRITICALZero Day

Patch Tuesday - July 2026

Microsoft is publishing 622 vulnerabilities on July 2026 Patch Tuesday , including a record-breaking 416 Windows vulnerabilities. Microsoft is aware of exploitation in the wild for two of the vulnerabilities published today, both of which are listed on CISA KEV, as well as public disclosure for one other. As usual, browser vulns are not included in the Patch Tuesday count above. Rapid7 noted last

CVE-2026-55040CVE-2026-56164
Rapid7
HIGHVulnerability

NVD HIGH: CVE-2026-56181 — Origin validation error in Windows Network Address Translation (NAT) allows an u...

Origin validation error in Windows Network Address Translation (NAT) allows an unauthorized attacker to perform spoofing over an adjacent network.

CVE-2026-56181
NIST NVD

References (1)

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56181PatchVendor Advisory