Cyber Resilience

CVE-2024-38021

High

Published: 09 July 2024

Published
09 July 2024
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.0855 92.6th percentile
Risk Priority 23 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2024-38021 is a high-severity Improper Input Validation (CWE-20) vulnerability in Microsoft Office. Its CVSS base score is 8.8 (High).

Operationally, ranked in the top 7.4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

Deeper analysis

Microsoft Outlook contains a remote code execution vulnerability tracked as CVE-2024-38021 and published on 2024-07-09. The flaw carries a CVSS 3.1 score of 8.8 with the vector AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H and is associated with CWE-20. It affects the Outlook client component in Microsoft 365 and on-premises deployments.

An unauthenticated remote attacker can exploit the issue by sending a specially crafted message or file that triggers code execution once a user interacts with it, resulting in full confidentiality, integrity, and availability impact on the target system without requiring prior authentication.

Microsoft has published remediation guidance and security updates through its Security Response Center at the listed MSRC URLs, directing administrators to apply the corresponding Outlook patches.

EPSS for the CVE rose from lower values after disclosure to a peak of 0.1612 on 2025-12-11 before receding to the current 0.0855, indicating a period of increased exploitation interest that later subsided.

EU & UK References

Vulnerability details

Microsoft Outlook Remote Code Execution Vulnerability

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

microsoft
365 apps
all versions
microsoft
office
2016, 2019
microsoft
office long term servicing channel
2021

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-20

Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.

addresses: CWE-20

Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.

addresses: CWE-20

Directly implements checks on information inputs to reject invalid data before processing.

addresses: CWE-20

Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.

References