#VU102803 Information disclosure in Windows and Windows Server - CVE-2025-21308

Vulnerability identifier: #VU102803

Vulnerability risk: Medium

CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2025-21308

CWE-ID: CWE-200

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Windows
Operating systems & Components / Operating system
Windows Server
Operating systems & Components / Operating system

Vendor: Microsoft

Description

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to excessive data output by the application in Windows Themes. A remote attacker can trick a victim to load a malicious file onto a vulnerable system and gain unauthorized access to sensitive information on the system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Windows: before 10 21H2, 10 22H2, 10 1507, 10 1607, 10 1809, 11 22H2, 11 23H2, 11 24H2, 10 21H2, 10 21H2, 10 21H2, 10 21H2, 10 21H2, 10 21H2, 10 21H2, 10 21H2

Windows Server: before 2012 R2, 2012, 2016, 2022, 2025, 2012 R2, 2012 R2, 2012 R2, 2012 R2

---

External links
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2025-21308

---

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.