SB2026011371 - Privilege escalation in Microsoft Windows HTTP.sys
Published: January 13, 2026
Security Bulletin ID
SB2026011371
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Code execution
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Improper access control (CVE-ID: CVE-2026-20929)
CWE-ID: CWE-284 - Improper Access Control
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote user to compromise the affected system.
The vulnerability exists due to improper access restrictions Windows HTTP.sys. A remote user can send specially crafted packets to the system and execute arbitrary code with SYSTEM privileges.
Note, successful exploitation of the vulnerability requires an Service Principal Name (SPN) that is registered to an account that no longer exists or is not in use.
Remediation
Install update from vendor's website.