Cyber Resilience

CVE-2024-21378

HighRCE

Published: 13 February 2024

Published
13 February 2024
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.2731 96.5th percentile
Risk Priority 34 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2024-21378 is a high-severity Code Injection (CWE-94) vulnerability in Microsoft 365 Apps. Its CVSS base score is 8.8 (High).

Operationally, ranked in the top 3.5% 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-2024-21378 and assigned CWE-94. The flaw carries a CVSS 3.1 score of 8.8 reflecting network attack vector, low complexity, low required privileges, and no user interaction, enabling an attacker to achieve full confidentiality, integrity, and availability impact on affected Outlook installations.

An authenticated attacker with network access can send specially crafted messages or content that trigger code execution on the target system, resulting in complete compromise of the Outlook process and potentially the underlying host.

Microsoft has published an advisory for CVE-2024-21378 in its security update guide at the referenced URL. The current EPSS score of 0.2731 matches its recorded peak and does not indicate a post-disclosure rise in observed exploitation interest.

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
2019
microsoft
office long term servicing channel
2021
microsoft
outlook
2016

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-94

Makes persistent code injection into loaded programs impossible when the executable image itself resides on hardware-protected read-only media.

addresses: CWE-94

Dynamically generated code can be produced and executed inside the isolated chamber, preventing host compromise from code-injection payloads.

addresses: CWE-94

Validates inputs used in dynamic code generation to block injected directives.

addresses: CWE-94

Directly prevents execution of attacker-supplied code written into data memory regions.

References