CVE-2021-22656Network attack vector

Unauthenticated file disclosure via unvalidated servlet paths

Published Feb 11, 2021 · Updated Aug 3, 2024

Path traversal in CommandServlet in Advantech iView before 5.7.03.6112 allows remote attackers to read sensitive files over HTTP. The servlet uses a user-supplied path in file operations without validating that the resolved path remains within an allowed directory. No authentication or user interaction is required, and successful requests disclose files readable by the SYSTEM-context service without reported write or execution capability.

CVSS severity7.5
High
EPSS probability3.23%
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 CommandServlet in Advantech iView before 5.7.03.6112 allows remote attackers to read sensitive files over HTTP. The servlet uses a user-supplied path in file operations without validating that the resolved path remains within an allowed directory. No authentication or user interaction is required, and successful requests disclose files readable by the SYSTEM-context service without reported write or execution capability.

The record

CVE
CVE-2021-22656
Published
Feb 11, 2021
Updated
Aug 3, 2024
Vendor
Advantech
Product
iView
Classifications
CWE-22, T1005, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record 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=iView versions prior to v5.7.03.6112

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Advantech · iViewversion=iView versions prior to v5.7.03.6112

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
5.0NIST NVDAV:N/AC:L/Au:N/C:P/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1005Data from Local System
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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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