CVE-2025-21186
Published: 14 January 2025
Summary
CVE-2025-21186 is a high-severity Heap-based Buffer Overflow (CWE-122) vulnerability in Microsoft Office Long Term Servicing Channel. 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 21.5% 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).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
SI-2 requires timely remediation of flaws, directly addressing the heap-based buffer overflow in Microsoft Access by applying vendor patches to prevent exploitation via malicious files.
SI-16 enforces memory protections like ASLR and DEP, which mitigate heap-based buffer overflow exploits allowing arbitrary code execution in Microsoft Access.
SI-3 deploys malicious code protection tools to scan and block malicious Access files before user interaction triggers the remote code execution vulnerability.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Heap buffer overflow in Microsoft Access enables client-side RCE when a user opens a malicious file (T1204.002), directly mapping to exploitation for client execution (T1203).
NVD Description
Microsoft Access Remote Code Execution Vulnerability
Deeper analysisAI
CVE-2025-21186 is a remote code execution vulnerability affecting Microsoft Access. Published on 2025-01-14, 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-122 (Heap-based Buffer Overflow) along with NVD-CWE-noinfo.
The vulnerability can be exploited by an attacker with local access to the target system. Exploitation requires low attack complexity and no special privileges, but user interaction is necessary, such as convincing the user to open a malicious file or perform a specific action within Microsoft Access. Successful exploitation allows the attacker to achieve high-impact remote code execution, potentially compromising confidentiality, integrity, and availability by running arbitrary code in the context of the affected application.
The Microsoft Security Response Center (MSRC) provides detailed guidance on this vulnerability, including patch information and mitigation recommendations, at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21186. Security practitioners should consult this advisory for deployment instructions.
Details
- CWE(s)