Is CVE-2026-83511 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-83511 being exploited in the wild.

How severe is CVE-2026-83511?

High severity, with a CVSS score of 7.4, published 13 October 2026.

Is there a fix for CVE-2026-83511?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-83511 attacked?

It is attacked over the network, in a hosted service.

Am I affected by CVE-2026-83511?

Check whether you run Microsoft Active Directory Federation Services, Microsoft Windows 10 1607, Microsoft Windows 10 1809 or one of the others listed. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-83511: Microsoft Active Directory Federation Services weak authentication

CVE-2026-83511 · Severity: high · CVSS 7.4 · Published 2026-10-13

Active Directory Federation Services (AD FS) is Microsoft's identity and access management service used to authenticate users across enterprise networks and cloud applications. A weak authentication vulnerability allows attackers to spoof user identities and gain unauthorized access to protected resources without valid credentials. This could enable account takeover, data theft, and lateral movement within corporate environments.

Technologies: Microsoft Active Directory Federation Services, Microsoft Windows 10 1607, Microsoft Windows 10 1809, Microsoft Windows Server 2012, Microsoft Windows Server 2016, Microsoft Windows Server 2019, Microsoft Windows Server 2022, Microsoft Windows Server 2025. Vendors: Microsoft.

Quick answers

Is CVE-2026-83511 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-83511 being exploited in the wild.
How severe is CVE-2026-83511?: High severity, with a CVSS score of 7.4, published 13 October 2026.
Which products and versions are affected?: Microsoft Active Directory Federation Services.
Is there a fix for CVE-2026-83511?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-83511 attacked?: It is attacked over the network, in a hosted service.
Am I affected by CVE-2026-83511?: Check whether you run Microsoft Active Directory Federation Services, Microsoft Windows 10 1607, Microsoft Windows 10 1809 or one of the others listed. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A weak authentication flaw in AD FS permits an unauthenticated attacker to perform identity spoofing via network access. The vulnerability requires no user interaction and allows an attacker to impersonate legitimate users and gain unauthorized access to systems and data that rely on AD FS for authentication. A fix is available from Microsoft.

Affected products

Microsoft Active Directory Federation Services

Timeline

2026-10-13: disclosed

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83511

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