Quick answers
- Is CVE-2026-83645 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-83645 being exploited in the wild.
- How severe is CVE-2026-83645?
- High severity, with a CVSS score of 7.5, published 13 October 2026.
- Which products and versions are affected?
- Microsoft Active Directory Federation Services.
- Is there a fix for CVE-2026-83645?
- 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-2026-83645 attacked?
- It is attacked over the network, in a hosted service.
- Am I affected by CVE-2026-83645?
- 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
The vulnerability is a resource exhaustion flaw in AD FS where incoming requests are not properly rate-limited or throttled, allowing an attacker to send unlimited requests that exhaust server memory, CPU, or connection limits. The attack requires network access to the AD FS endpoint and can be executed without authentication. Successful exploitation causes a denial of service condition affecting authentication services across the enterprise.
Affected products
- Microsoft Active Directory Federation Services
Timeline
- 2026-10-13: advisory