How severe is CVE-2026-56179?

CVE-2026-56179 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-2026-56179 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-56179?

CVE-2026-56179 primarily affects Microsoft Windows 11 24h2. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-56179?

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-2026-56179 published?

CVE-2026-56179 was published on 2026-08-11 and last updated on 2026-08-13.

CVE-2026-56179

CVE-2026-56179 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% (15th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-346
Affected product: Microsoft Windows 11 24h2
Published: 2026-08-11
Last modified: 2026-08-13

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-2026-56179?: Origin validation error in Windows Network Address Translation (NAT) allows an unauthorized attacker to perform spoofing over an adjacent network.
How severe is CVE-2026-56179?: CVE-2026-56179 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-2026-56179 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-56179?: CVE-2026-56179 primarily affects Microsoft Windows 11 24h2. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-56179?: 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-2026-56179 published?: CVE-2026-56179 was published on 2026-08-11 and last updated on 2026-08-13.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56179

Affected products (7)

cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:x64:*

More vulnerabilities in Microsoft Windows 11 24h2

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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-2026-16375 — 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…
CVE-2026-16349 — Critical (CVSS 9.8): Same-origin policy bypass in the DOM: Navigation component. This vulnerability was fixed in Firefox 153, Firefox ESR…
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CVE-2026-6508 — Critical (CVSS 9.8): Origin Validation Error vulnerability in TUBITAK BILGEM Software Technologies Research Institute Liderahenk allows…

Browse all CWE-346 vulnerabilities →