Cyber Resilience

CVE-2021-4463

HighPublic PoC

Published: 12 November 2025

Published
12 November 2025
Modified
15 April 2026
KEV Added
Patch
CVSS Score v4 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0185 83.4th percentile
Risk Priority 19 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-4463 is a high-severity Path Traversal (CWE-22) vulnerability. Its CVSS base score is 8.7 (High).

Operationally, ranked in the top 16.6% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

Longjing Technology BEMS API versions up to and including 1.21 contains an unauthenticated arbitrary file download vulnerability in the 'downloads' endpoint. The 'fileName' parameter is not properly sanitized, allowing attackers to craft traversal sequences and access sensitive files outside the…

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intended directory.

CWE(s)

Related Threats

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

Affected Assets

Longjing Technology BEMS API
inferred from references and description; NVD did not file a CPE for this CVE

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-552

Controls on authorized publication limit files and directories with nonpublic data from becoming accessible to external parties.

addresses: CWE-552

Controlling and documenting P2P file sharing prevents files and directories from being made accessible to external parties for unauthorized distribution.

addresses: CWE-552

Identifying and documenting file and directory locations allows restriction of access to external parties.

addresses: CWE-552

Protecting backup files ensures they are not accessible to external parties or unauthorized spheres.

addresses: CWE-552

Sanitizing equipment before off-site maintenance reduces the risk of files or directories containing sensitive data becoming accessible to external parties.

addresses: CWE-552

Policy restricts media access to authorized parties only, preventing exposure of resources to external or unauthorized actors.

addresses: CWE-552

Media access restrictions prevent files or directories from being accessible to external parties.

addresses: CWE-552

Employing and evaluating controls at documented alternate sites makes files and directories less likely to be accessible to external parties through physical or environmental weaknesses.

References