EUVD-2026-43986
GHSA-q56f-qhqm-x6f8
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Unauthenticated network attacker triggers the overflow with no user interaction (AV:N/AC:L/PR:N/UI:N); heap RCE in the service yields full C:H/I:H/A:H, though the FTP role must be enabled.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
2DescriptionCVE.org
Heap-based buffer overflow in Windows FTP Service allows an unauthorized attacker to execute code over a network.
AnalysisAI
Remote code execution in the Microsoft Windows FTP Service allows an unauthenticated network attacker to run arbitrary code by triggering a heap-based buffer overflow (CWE-122). The flaw affects the FTP service across a broad range of Windows 10, Windows 11, and Windows Server (2019/2022/2025) builds and carries a critical CVSS 9.8 rating with no authentication or user interaction required. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the target host to have the Microsoft Windows FTP service installed, enabled, and network-reachable by the attacker - this optional IIS FTP role is not present or running in a default Windows installation, which is the primary factor limiting real-world exposure. … 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:H/I:H/A:H) describes a worst-case profile: network-reachable, low complexity, no privileges, no user interaction, with full confidentiality, integrity, and availability impact - hence the 9.8 score. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker who can reach an exposed Windows FTP service over the network sends a crafted FTP command containing an oversized or malformed argument that overflows a heap buffer during parsing, corrupting adjacent heap structures. By shaping the heap and overflow contents, the attacker redirects execution to run arbitrary code in the FTP service context - all without any credentials or user interaction. … |
| Remediation | Patch available per vendor advisory - apply the Microsoft security update for CVE-2026-49172 to all affected Windows 10, Windows 11, and Windows Server 2019/2022/2025 systems (including Server Core) via Windows Update or your patch-management tooling, using the build-specific fixed versions listed at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-49172 (exact fix build numbers were not provided in this input and should be taken from that advisory). … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, identify and inventory all systems running Microsoft Windows FTP Service, including Windows 10, Windows 11, Windows Server 2019, Windows Server 2022, and Windows Server 2025 installations, with particular attention to internet-facing or externally accessible systems. …
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Same weakness CWE-122 – Heap-based Buffer Overflow
View allSame technique Heap Overflow
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External POC / Exploit Code
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