CVE-2025-21354
Microsoft Office Long Term Servicing Channel 2021 … 2024
Raw vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2025-21354 is a high-severity Untrusted Pointer Dereference (CWE-822) vulnerability in Microsoft Office Long Term Servicing Channel. Its CVSS base score is 8.4 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 42% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
Microsoft Excel is affected by a remote code execution vulnerability, CVE-2025-21354, which carries a CVSS 3.1 score of 8.4 under the vector AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. The issue is linked to CWE-822 and enables arbitrary code execution on affected installations of the spreadsheet application.
An attacker with local access to a vulnerable system can trigger the flaw without credentials or user interaction, achieving full control over confidentiality, integrity, and availability of the host. The attack surface is therefore limited to scenarios where an adversary can already place or invoke malicious content locally.
The Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21354 supplies official remediation details. Exploitation probability has stayed low, with the EPSS score reaching a peak of only 0.0173.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-2418
Vulnerability Data
Microsoft Excel Remote Code Execution Vulnerability
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover instances where untrusted data is turned into a pointer and dereferenced.
Validating all information inputs stops untrusted values from being accepted and converted into dereferenceable pointers.
Memory-protection mechanisms limit the damage from an invalid pointer dereference without stopping the root coding flaw.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly prevent introduction of untrusted pointer handling during development.
Runtime monitoring of software and data can detect adverse events resulting from exploitation of the weakness.
Vulnerability identification processes can discover instances of this weakness via code review or scanning.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect pointer-dereference flaws before release.
Secure development lifecycle includes pointer-safety practices that reduce untrusted pointer dereference risk.
Application security requirements can mandate validation of pointers obtained from untrusted sources.
Secure architecture principles discourage direct use of untrusted values as pointers.
Secure coding standards explicitly forbid dereferencing pointers derived from untrusted input.