CVE-2021-21804Public exploitNetwork attack vector

Authenticated PHP code execution via unsanitized include

Published Jul 16, 2021 · Updated Aug 3, 2024

Local file inclusion in Advantech R-SeeNet 2.4.12 allows remote authenticated users to execute arbitrary PHP code via crafted HTTP requests. The options.php script copies the user-controlled sub_opt parameter directly into include($sub_opt.".php") without sanitization, permitting file reads or PHP execution through stream wrappers. Access requires a logged-in account, although the guest role can load options; successful exploitation can disclose configuration data and execute code with the web server’s privileges.

CVSS severity8.1
High
EPSS probability3.71%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Local file inclusion in Advantech R-SeeNet 2.4.12 allows remote authenticated users to execute arbitrary PHP code via crafted HTTP requests. The options.php script copies the user-controlled sub_opt parameter directly into include($sub_opt.".php") without sanitization, permitting file reads or PHP execution through stream wrappers. Access requires a logged-in account, although the guest role can load options; successful exploitation can disclose configuration data and execute code with the web server’s privileges.

The record

CVE
CVE-2021-21804
Published
Jul 16, 2021
Updated
Aug 3, 2024
Vendor
Advantech
Product
R-SeeNet
Classifications
CWE-22, CWE-98, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 16, 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=Advantech R-SeeNet 2.4.12 (20.10.2020)

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Advantech · R-SeeNetversion=Advantech R-SeeNet 2.4.12 (20.10.2020)

Published CVSS scores

8.1Cisco TalosCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-98Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion')
T1190Exploit Public-Facing Application

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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