How severe is CVE-2026-56181?

CVE-2026-56181 has a CVSS 3.x base score of 8.3, rated high severity. It is exploitable over an adjacent network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-56181 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-56181?

CVE-2026-56181 primarily affects Microsoft Windows 11 24h2. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-56181?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-56181 published?

CVE-2026-56181 was published on 2026-07-14 and last updated on 2026-07-22.

CVE-2026-56181

CVE-2026-56181 is a high-severity vulnerability in Microsoft Windows 11 24h2 with a CVSS 3.x base score of 8.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-346.

Key facts

Severity: High (CVSS 3.x base score 8.3)
EPSS exploit prediction: 0% (18th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-346
Affected product: Microsoft Windows 11 24h2
Published: 2026-07-14
Last modified: 2026-07-22

Description

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

Frequently asked questions

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.
How severe is CVE-2026-56181?: CVE-2026-56181 has a CVSS 3.x base score of 8.3, rated high severity. It is exploitable over an adjacent network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-56181 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-56181?: CVE-2026-56181 primarily affects Microsoft Windows 11 24h2. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-56181?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-56181 published?: CVE-2026-56181 was published on 2026-07-14 and last updated on 2026-07-22.

References

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

Affected products (4)

cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:*

More vulnerabilities in Microsoft Windows 11 24h2

CVE-2026-57092 — Critical (CVSS 9.9): Use after free in Windows VMSwitch allows an authorized attacker to elevate privileges over a network.
CVE-2025-49708 — Critical (CVSS 9.9): Use after free in Microsoft Graphics Component allows an authorized attacker to elevate privileges over a network.
CVE-2026-77493 — Critical (CVSS 9.8): Double free in Microsoft Graphics Component allows an unauthorized attacker to execute code over a network.
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CVE-2026-72982 — Critical (CVSS 9.8): Stack-based buffer overflow in Windows Netlogon allows an unauthorized attacker to execute code over a network.

All CVEs affecting Microsoft Windows 11 24h2 →

Other CWE-346 vulnerabilities

CVE-2026-42901 — Critical (CVSS 10.0): Origin validation error in Microsoft Entra ID allows an unauthorized attacker to elevate privileges over a network.
CVE-2026-84140 — Critical (CVSS 9.8): Site isolation issue in the DOM: Navigation component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2,…
CVE-2026-84133 — Critical (CVSS 9.8): Site isolation issue in the DOM: Push Subscriptions component. This vulnerability was fixed in Firefox 155, Firefox ESR…
CVE-2026-84129 — Critical (CVSS 9.8): Site isolation issue in the DOM: Navigation component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2,…
CVE-2026-16375 — Critical (CVSS 9.8): Site isolation issue in the Networking: HTTP component. This vulnerability was fixed in Firefox 153, Firefox ESR…
CVE-2026-16358 — Critical (CVSS 9.8): Site isolation issue in the Graphics: WebRender component. This vulnerability was fixed in Firefox 153, Firefox ESR…

Browse all CWE-346 vulnerabilities →