Which versions of Longjing Technology BEMS API are affected by CVE-2021-4463?

Organizations using Longjing Technology BEMS API versions up to and including 1.21 face significant risk from CVE-2021-4463, a path traversal vulnerability rated CVSS 8.7.

Is there a public PoC exploit available for CVE-2021-4463?

Yes, a public proof-of-concept exploit is available for CVE-2021-4463. Prioritise patching immediately. EPSS: 0.2%.

How to fix or mitigate CVE-2021-4463?

Within 7 days: Identify all affected systems and apply vendor patches promptly. Review file handling controls and restrict upload directories.

Longjing Technology BEMS API CVE-2021-4463

Q: What is the CVSS score of CVE-2021-4463?

CVE-2021-4463 has a CVSS 4.0 base score of 8.7 (High). CVSS vector: 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 exploitation probability: 0.2%.

HIGH

Path Traversal (CWE-22)

2025-11-12 disclosure@vulncheck.com

Path Traversal

8.7

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

8.7 HIGH

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Analysis Generated

Mar 28, 2026 - 19:21 vuln.today

PoC Detected

Nov 14, 2025 - 16:42 vuln.today

Public exploit code

CVE Published

Nov 12, 2025 - 22:15 nvd

HIGH 8.7

DescriptionCVE.org

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 intended directory.

AnalysisAI

Longjing Technology BEMS API versions up to and including 1.21 contains an unauthenticated arbitrary file download vulnerability in the 'downloads' endpoint. Rated high severity (CVSS 8.7), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Technical ContextAI

This vulnerability is classified as Path Traversal (CWE-22), which allows attackers to access files and directories outside the intended path. 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 intended directory.

Affected ProductsAI

See vendor advisory for affected versions.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate and canonicalize file paths. Use chroot or sandboxing. Reject input containing path separators or '../' sequences.