SB2026021065 - Multiple vulnerabilities in Microsoft Windows HTTP.sys

Description

This security bulletin contains information about 3 secuirty vulnerabilities.

1) Untrusted Pointer Dereference (CVE-ID: CVE-2026-21250)

The vulnerability allows a local user to escalate privileges on the target system.

The vulnerability exists due to untrusted pointer dereference in Windows HTTP.sys. A local user can gain elevated privileges on the system.

2) Untrusted Pointer Dereference (CVE-ID: CVE-2026-21232)

The vulnerability allows a local user to escalate privileges on the target system.

The vulnerability exists due to untrusted pointer dereference in Windows HTTP.sys. A local user can gain elevated privileges on the system.

3) Time-of-check Time-of-use (TOCTOU) Race Condition (CVE-ID: CVE-2026-21240)

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a time-of-check, time-of-use (TOCTOU) race condition in Windows HTTP.sys. A local user can gain elevated privileges on the target system.

Remediation

Install update from vendor's website.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21250
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21232
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21240