EUVD-2026-56372
GHSA-r648-f5mp-m4x9
Severity by source
AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Adjacent vector fits network-local http.sys exposure; PR:N confirmed by unauthenticated bypass nature; I:H for tampering impact; no confidentiality or availability impact observed.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
3DescriptionCVE.org
Partial string comparison in Windows HTTP Protocol Stack allows an unauthorized attacker to perform tampering over an adjacent network.
AnalysisAI
Tampering via partial string comparison in the Windows HTTP Protocol Stack (http.sys) exposes a broad range of Windows client and server editions to integrity compromise by unauthenticated adjacent-network attackers. Affected platforms span Windows 10 1607 through Windows 11 26H1 and Windows Server 2012 through Server 2025, with Microsoft tagging the issue as an authentication bypass rooted in CWE-187. No public exploit has been identified at time of analysis, and Microsoft has released patched builds across all affected product lines.
Technical ContextAI
The Windows HTTP Protocol Stack - implemented as the kernel-mode driver http.sys - underlies Windows web services including IIS and the Windows Remote Management stack. CWE-187 (Improper Handling of Partial String Comparison) describes a class of logic flaws where security-critical string comparisons evaluate only a prefix, suffix, or substring of the target value rather than the complete string. In an HTTP context, this flaw likely affects comparison of authentication tokens, Host header values, or URL path segments, permitting a crafted request whose partial value satisfies the flawed check while the full string would not - effectively circumventing authentication or routing logic. The adjacent network attack vector (AV:A) bounds exploitation to the same local network segment, broadcast domain, or point-to-point link as the target, ruling out direct internet exploitation but remaining highly relevant in enterprise LAN environments, shared hosting infrastructure, and cloud virtual networks.
RemediationAI
Microsoft has released patched cumulative updates for all affected product lines; organizations should apply the relevant update as soon as operationally feasible. Target fixed build numbers are: Windows Server 2012 - 6.2.9200.26279 or later; Windows Server 2012 R2 - 6.3.9600.23337 or later; Windows Server 2016 and Windows 10 1607 - 10.0.14393.9418 or later; Windows Server 2019 and Windows 10 1809 - 10.0.17763.9115 or later; Windows Server 2022 - 10.0.20348.5499 or later; Windows Server 2025 - 10.0.26100.33296 or later; Windows 10 21H2 - 10.0.19044.7663 or later; Windows 10 22H2 - 10.0.19045.7663 or later; Windows 11 23H2 - 10.0.22631.7517 or later; Windows 11 24H2 - 10.0.26100.9168 or later; Windows 11 25H2 - 10.0.26200.9168 or later; Windows 11 26H1 - 10.0.28000.2704 or later. Where immediate patching is not feasible, enforce network segmentation to restrict adjacency to http.sys-exposed systems, limiting access to trusted hosts via host-based firewall rules or VLAN controls - this reduces the exploitable surface without eliminating the flaw and imposes no functional degradation for legitimate HTTP consumers. Full vendor guidance is available at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62750.
More in Windows 10 1607
View allWindows MSHTML component contains a remote code execution vulnerability that allows attackers to craft malicious ActiveX
<p>A remote code execution vulnerability exists when the Windows Print Spooler service improperly performs privileged fi
Windows MSDT (Microsoft Support Diagnostic Tool) allows remote code execution when called via the ms-msdt URL protocol f
The SMBv1 server in Microsoft Windows Vista SP2; Windows Server 2008 SP2 and R2 SP1; Windows 7 SP1; Windows 8.1; Windows
The Windows VBScript engine contains a remote code execution vulnerability in object handling that allows full system co
Windows Print Spooler Remote Code Execution Vulnerability. Rated high severity (CVSS 7.8), this vulnerability is no auth
The Win32k kernel-mode driver in Windows Vista through Windows Server 2016 allows local privilege escalation, exploited
Windows Search Remote Code Execution Vulnerability. Rated high severity (CVSS 7.5), this vulnerability is remotely explo
Denial of service against HTTP/2 server implementations allows remote unauthenticated attackers to exhaust server resour
Windows Kernel contains a TOCTOU race condition vulnerability allowing local privilege escalation, exploited by the OilR
An elevation of privilege vulnerability exists in Windows when the Win32k component fails to properly handle objects in
An elevation of privilege vulnerability exists in Windows when the Win32k component fails to properly handle objects in
Same weakness CWE-187 – Partial String Comparison
View allSame technique Authentication Bypass
View allShare
External POC / Exploit Code
Leaving vuln.today