CVE-2026-56181: exploitation status and patch state

CVE-2026-56181 · CVSS 8.3 HIGH · patch available

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

Is CVE-2026-56181 exploited?

• Not in the CISA KEV catalog.
• Public exploit code: none found in monitored sources.

Which products and versions are affected?

No affected package list recorded here yet.

Is there a patch?

• KB5099536
• KB5101650
• KB5101649

What PlainSec published about CVE-2026-56181

• Shared NAT Is Not a Safe Isolation Boundary (2026-08-08)

Primary sources

• NVD record
• Microsoft KB5099536
• Microsoft KB5101650
• Microsoft KB5101649

What this record does not say

• No EPSS score.
• No affected package data.

KEV and EPSS are re-checked daily. Record last updated 2026-08-14.