CVE-2021-4463Public exploitNetwork attack vector

Unauthenticated file disclosure via filename path traversal

Published Nov 12, 2025 · Updated Nov 12, 2025

Path traversal in Shenzhen Longjing Technology Co., Ltd. BEMS API 1.21 and earlier allows remote attackers to read arbitrary server files. The unauthenticated /api/downloads endpoint uses the fileName parameter for downloads without rejecting traversal sequences. A crafted relative path escapes the intended directory and discloses files readable by the service account, including password and shadow files in the published exploit.

CVSS severity8.7
High
EPSS probability1.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in Shenzhen Longjing Technology Co., Ltd. BEMS API 1.21 and earlier allows remote attackers to read arbitrary server files. The unauthenticated /api/downloads endpoint uses the fileName parameter for downloads without rejecting traversal sequences. A crafted relative path escapes the intended directory and discloses files readable by the service account, including password and shadow files in the published exploit.

The record

CVE
CVE-2021-4463
Published
Nov 12, 2025
Updated
Nov 12, 2025
Vendor
Shenzhen Longjing Technology Co., Ltd.
Product
BEMS API
Classifications
CWE-22, CWE-552, CAPEC-126, T1005
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 12, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 12, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=1.21

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Shenzhen Longjing Technology Co., Ltd. · BEMS APIversion=0 <=1.21

Published CVSS scores

8.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-552Files or Directories Accessible to External Parties
CAPEC-126Path Traversal
T1005Data from Local System

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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