Zero-day vulnerability in Windows

Information disclosure
CVE-2026-20805

Vulnerability details

Advisory: SB2026011370 - Information disclosure in Microsoft Desktop Window Manager

Vulnerable component: Windows

CVE-ID: CVE-2026-20805

CVSSv3 score: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:H/RL:O/RC:C

CWE-ID: CWE-200 - Exposure of sensitive information to an unauthorized actor

Description:

The vulnerability allows a local user to gain access to potentially sensitive information.

The vulnerability exists due to excessive data output by the Desktop Windows Manager. A local user can gain access to a section address from a remote ALPC port, which is user-mode memory.

Note, the vulnerability is being actively exploited in the wild. 

External links:

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20805

About zero-day vulnerabilities

Zero-day vulnerability is an undisclosed vulnerability in software that hackers can exploit to compromise computer programs, gain unauthorized access to sensitive data, penetrate networks, etc. We consider vulnerability a zero-day when there is no solution provided from software vendor and the vulnerability is being actively exploited by malicious actors.

Zero-day candidate is a potential zero-day vulnerability in software which might have been used in targeted attacks, however there is no evidence to support this suggestion.