#VU102799 Deserialization of Untrusted Data in Microsoft Office LTSC and Microsoft 365 Apps for Enterprise - CVE-2025-21364

Vulnerability identifier: #VU102799

Vulnerability risk: High

CVSSv4.0: 5.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2025-21364

CWE-ID: CWE-502

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Microsoft Office LTSC
Client/Desktop applications / Other client software
Microsoft 365 Apps for Enterprise
Client/Desktop applications / Office applications

Vendor: Microsoft

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to insecure input validation when processing serialized data in Microsoft Excel. A remote attacker can trick a victim to open a specially crafted file and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Microsoft Office LTSC: 2024

Microsoft 365 Apps for Enterprise: 32-bit Systems, 64-bit Systems

---

External links
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2025-21364

---

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.