Threat Intelligence / CVE / CVE-2026-56181

CVE-2026-56181 — Microsoft Windows 11 Version 24H2

CVSS v3.1 8.3 (HIGH) · EPSS 0.2% (higher than 14.7% of all scored CVEs) · Priority 4.7/10 · Published 2026-07-14

As of 2026-08-06, CVE-2026-56181 is a HIGH-severity vulnerability in Microsoft Windows 11 Version 24H2, CVSS v3.1 8.3, EPSS 0.2% (14.7th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-56181, most recently “NatJack: NAT Connection-Tracking Manipulation Attacks Hijack TCP Sessions Across Windows, Linux, and macOS (CVE-2026-56181, CVE-2026-63913)”.

Last updated: 2026-08-06

What is CVE-2026-56181?

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

The record classifies CVE-2026-56181 under weakness class CWE-346. Its CVSS v3 base vector states that the flaw is reachable from an adjacent network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 5 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 60 days ago.

Severity and exploitation probability

CVSS v3.1 base score
8.3 — HIGH
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C
EPSS (FIRST)
0.2% probability of exploitation in the next 30 days, higher than 14.7% of all scored CVEs
CISA KEV
Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority
4.7/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published
2026-07-14, last modified 2026-08-06

Is CVE-2026-56181 being exploited?

No public exploitation evidence for CVE-2026-56181 is recorded in the sources Threadlinqs tracks — CISA KEV, Exploit-DB, public proof-of-concept repositories and ProjectDiscovery Nuclei — as of 2026-08-06. That is an absence of evidence in those feeds, not a guarantee that the vulnerability is unexploited.

Affected products and versions

How to fix CVE-2026-56181

The record marks a vendor fix as available for CVE-2026-56181. Patch reference: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56181. Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56181. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

Threat activity tracking CVE-2026-56181

1 tracked threat in the Threadlinqs corpus references CVE-2026-56181, either in the campaign’s CVE list or as an indicator on the campaign record.

Sources

Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.

Vendor advisory and patch

Full detection coverage & IOCs for threats exploiting CVE-2026-56181 are available via the Threadlinqs MCP server (Purple tier). View plans →

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