CVE-2021-27328Public exploitNetwork attack vector

Authenticated path traversal to sensitive files

Published Feb 19, 2021 · Updated Jul 9, 2026

Directory traversal in Yeastar NeoGate TG400 91.3.0.3 allows remote authenticated users to read sensitive firmware and configuration data. The cgi/WebCGI handler accepts the 1404 parameter and resolves ../../ path segments to files such as /bin/firmware_detect and /etc/passwd without restricting the pathname to an intended directory. Access requires an authenticated portal account; the demonstrated impact is confidential data disclosure, including firmware decryption material, passwords, and system files.

CVSS severity6.5
Medium
EPSS probability6.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Directory traversal in Yeastar NeoGate TG400 91.3.0.3 allows remote authenticated users to read sensitive firmware and configuration data. The cgi/WebCGI handler accepts the 1404 parameter and resolves ../../ path segments to files such as /bin/firmware_detect and /etc/passwd without restricting the pathname to an intended directory. Access requires an authenticated portal account; the demonstrated impact is confidential data disclosure, including firmware decryption material, passwords, and system files.

The record

CVE
CVE-2021-27328
Published
Feb 19, 2021
Updated
Jul 9, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-22, T1005
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 19, 2021CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.0NIST NVDAV:N/AC:L/Au:S/C:P/I:N/A:N
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path 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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