CVE-2026-50324: Windows Active Directory Federation Services Denial of Service Vulnerability

mediumCVSS 5.9CVE-2026-50324

Loop with unreachable exit condition ('infinite loop') in Active Directory Federation Services (AD FS) allows an unauthorized attacker to deny service over a network.

CSIRTS triage

vendor: Microsoft product: Active Directory Federation Services Denial of service

What: Loop with unreachable exit condition ('infinite loop') in Active Directory Federation Services (AD FS) allows an unauthorized attacker to deny service over a network.
Who is affected: Deployments of Active Directory Federation Services.
Urgency: Remediation is important due to medium severity and potential for denial of service.
Action: Apply the latest security patch for Active Directory Federation Services.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 5.9
Published: 2026-07-14
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50324

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-503240.78% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 52% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-50324	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

mediumCVE-2026-50324: Loop with unreachable exit condition ('infinite loop') in Active Directory Federation Services…nvd
unknownexploitedNCSC-2026-0231 [1.00] [M/H] Vulnerabilities fixed in Microsoft Windowsncsc-nl

Recent advisories for Windows Active Directory

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

highCVE-2026-54115: Integer overflow or wraparound in Windows Active Directory allows an authorized attacker to el…nvd · 2026-07-14
highCVE-2026-50682: Out-of-bounds read in Windows Active Directory allows an authorized attacker to deny service o…nvd · 2026-07-14
highCVE-2026-55001: Improper certificate validation in Windows Active Directory allows an authorized attacker to e…nvd · 2026-07-14
highCVE-2026-54119: Loop with unreachable exit condition ('infinite loop') in Windows Active Directory allows an u…nvd · 2026-07-14
highCVE-2026-50368: Windows Active Directory Federation Services Denial of Service Vulnerabilitymsrc · 2026-07-14
highCVE-2026-50355: Windows Active Directory Federation Services Denial of Service Vulnerabilitymsrc · 2026-07-14