EUVD-2026-43866
GHSA-39q5-6p3f-g6gf
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Unauthenticated network-reachable ADFS endpoint (AV:N/PR:N/UI:N) with a low-complexity request that crashes the service; pure DoS so C:N/I:N and A:H.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
2DescriptionCVE.org
Stack-based buffer overflow in Active Directory Federation Services allows an unauthorized attacker to deny service over a network.
AnalysisAI
Remote denial of service in Microsoft Active Directory Federation Services (ADFS) allows an unauthenticated network attacker to crash the service via a stack-based buffer overflow (CWE-121). The flaw affects the ADFS role across Windows Server 2012 through 2025 (and the underlying Windows 10 1607/1809 servicing components), carries a CVSS 7.5 availability-only score, and was reported by Microsoft with a patch available. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires that the target host has the Active Directory Federation Services role installed and that its federation endpoint is reachable by the attacker over the network (AV:N); per the CVSS vector no authentication (PR:N) and no user interaction (UI:N) are required, so any network-reachable ADFS listener can be targeted against default configurations. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) describes a low-complexity, unauthenticated, network-reachable attack with high availability impact but no confidentiality or integrity impact - a pure denial of service, not remote code execution, which is why the score caps at 7.5 rather than critical. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker who can reach an internet- or DMZ-exposed ADFS federation endpoint sends a single crafted request whose oversized field overflows a stack buffer in the ADFS request parser, terminating the service and dropping single sign-on for all relying-party applications until it restarts. The attacker can repeat the request to sustain the outage. … |
| Remediation | Patch available per vendor advisory - apply the Microsoft security update for CVE-2026-50368 to all Windows Server systems running the ADFS role (2012, 2012 R2, 2016, 2019, 2022, and 2025, including Server Core installations) using the guidance at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50368; the input does not include a specific KB or build number, so pull the exact patched build for each OS version from that advisory. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, identify and inventory all ADFS deployments in your environment (Windows Server 2012 R2 through 2025) and document business criticality for each instance. …
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Same weakness CWE-121 – Stack-based Buffer Overflow
View allSame technique Buffer Overflow
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External POC / Exploit Code
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