Cyber Resilience

CVE-2021-42099

Critical

Published: 30 November 2021

Published
30 November 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.2241 96.0th percentile
Risk Priority 33 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-42099 is a critical-severity Unrestricted Upload of File with Dangerous Type (CWE-434) vulnerability in Zohocorp Manageengine M365 Manager Plus. Its CVSS base score is 9.8 (Critical).

Operationally, ranked in the top 4.0% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

Zoho ManageEngine M365 Manager Plus before 4421 is vulnerable to file-upload remote code execution.

CWE(s)

Related Threats

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

Affected Assets

zohocorp
manageengine m365 manager plus
all versions, build_4000, build_4001, build_4002, build_4003

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-434

Requiring identifiable owners for portable devices reduces the attack surface for unrestricted uploads of dangerous file types via anonymous media.

addresses: CWE-434

Dangerous file uploads can be detonated in the chamber to determine malice before any production write or execution occurs.

addresses: CWE-434

Prevents unrestricted writing of arbitrary or malicious firmware by keeping hardware write-protect enabled except under tightly controlled manual procedures.

addresses: CWE-434

Scans files from external sources on download/open/execute, blocking unrestricted uploads of dangerous file types.

References