CVE-2026-20929
Published: 13 January 2026
Summary
CVE-2026-20929 is a high-severity Improper Access Control (CWE-284) vulnerability in Microsoft Windows Server 2008. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 13.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
Threat & Defense at a Glance
Threat & Defense Details
Likely Mitigating ControlsAI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
The access control policy and procedures directly mandate and enforce proper access control mechanisms across the organization.
Device lock enforces restricted access until re-authentication, directly reducing unauthorized use of active sessions.
Supervision and review of access control activities directly detects and remediates improper access configurations or usages.
Explicitly identifying and documenting actions permitted without identification or authentication enforces proper access control boundaries by defining justified exceptions.
By automatically labeling outputs with security attributes, the control supports attribute-based enforcement and reduces exploitability of improper access control weaknesses.
Associating and retaining security attributes with data directly supports enforcement of access control decisions across storage, processing, and transmission.
Requiring prior authorization for each remote access type prevents improper access control over remote connections.
Requiring authorization of wireless access before allowing connections enforces proper access control for this access method.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Direct privilege escalation via exploitation of improper access control in kernel driver (HTTP.sys).
NVD Description
Improper access control in Windows HTTP.sys allows an authorized attacker to elevate privileges over a network.
Deeper analysisAI
CVE-2026-20929 is an improper access control vulnerability (CWE-284) in the Windows HTTP.sys kernel-mode driver, which handles HTTP requests in Windows operating systems. Published on 2026-01-13, it carries a CVSS v3.1 base score of 7.5 (AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H), indicating network accessibility with high attack complexity but significant impacts if exploited.
The vulnerability can be exploited by an authorized attacker with low privileges (PR:L) over a network (AV:N). Successful exploitation enables privilege escalation without user interaction (UI:N), leading to high confidentiality, integrity, and availability impacts (C:I:A:H) within the unchanged security scope (S:U).
Mitigation details are available in the Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20929.
Details
- CWE(s)