CVE-2025-21402
Published: 14 January 2025
Summary
CVE-2025-21402 is a high-severity Improper Restriction of Names for Files and Other Resources (CWE-641) vulnerability in Microsoft Office. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked in the top 33.0% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-16 (Memory Protection) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2025-21402 is a Remote Code Execution vulnerability in Microsoft Office OneNote. Published on January 14, 2025, it carries a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) and is associated with CWE-641 and NVD-CWE-noinfo.
The vulnerability requires local access (AV:L), low attack complexity (AC:L), no privileges (PR:N), and user interaction (UI:R), such as opening a malicious file. An attacker who can convince a user to interact with a specially crafted OneNote document can achieve remote code execution, resulting in high impacts to confidentiality, integrity, and availability (C:H/I:H/A:H) within the affected scope (S:U).
Microsoft's advisory on the MSRC Update Guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21402 provides details on mitigation, including available patches and security updates for affected OneNote versions.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-2462
Vulnerability details
Microsoft Office OneNote Remote Code Execution Vulnerability
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The CVE describes RCE achieved by convincing a user to open a specially crafted OneNote document (malicious file), directly enabling T1203 Exploitation for Client Execution and T1204.002 Malicious File.
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Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mitigates CVE-2025-21402 by requiring timely identification, reporting, and patching of the specific flaw in Microsoft OneNote.
Deploys anti-malware mechanisms to scan and prevent execution of malicious OneNote documents exploiting the RCE vulnerability.
Implements memory protection features like ASLR and DEP to block unauthorized code execution from the OneNote RCE exploit.