EUVD-2026-43802
GHSA-5h64-g45f-7wgq
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Network-reachable, unauthenticated, low-complexity resource-exhaustion DoS with no confidentiality or integrity impact, so AV:N/AC:L/PR:N/UI:N and A:H only.
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
Allocation of resources without limits or throttling in Windows HTTP.sys allows an unauthorized attacker to deny service over a network.
AnalysisAI
Denial of service in Microsoft Windows HTTP.sys allows remote unauthenticated attackers to exhaust system resources and make affected hosts unresponsive over the network. The flaw stems from missing resource limits/throttling (CWE-770) in the kernel-mode HTTP protocol stack, affecting a broad range of Windows client and server releases from Windows 10 1607 through Windows 11 26H1 and Windows Server 2016 through 2025. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | No special conditions - remote unauthenticated exploitation against network-reachable HTTP.sys listeners on affected Windows systems (CVSS AV:N/AC:L/PR:N/UI:N). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (7.5, High) indicates a low-complexity, network-reachable, unauthenticated attack with high availability impact but no confidentiality or integrity impact - a pure denial-of-service condition. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker with only network reachability to a Windows host's HTTP.sys listener sends a stream of specially crafted or high-volume HTTP requests designed to trigger unbounded resource allocation in the kernel driver. Because no authentication or user interaction is required (PR:N/UI:N) and attack complexity is low (AC:L), the attacker exhausts memory or connection resources, causing the web service or the entire host to become unresponsive. … |
| Remediation | Patch available per vendor advisory: apply the Microsoft security update for your specific Windows build as listed in the MSRC guidance at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-49787 (exact fixed KB/build numbers are provided there per OS version). … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, identify and inventory all affected Windows systems (Windows 10, Windows 11, and Windows Server 2016-2025) using Microsoft's MSRC advisory as authoritative source; prioritize systems hosting critical services or facing internet exposure. …
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External POC / Exploit Code
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