CVE-2021-47734Public exploitNetwork attack vector

Authenticated code execution via session-file inclusion

Published Dec 23, 2025 · Updated Mar 17, 2026

Local file inclusion in CMSimple 5.4 allows remote authenticated users to execute arbitrary code through a crafted PHP session file. The configuration save path accepts traversal in functions_file, causing CMSimple to include an attacker-controlled PHP session file. Administrative credentials and a valid CSRF token are required; the session-upload payload then runs commands under the web server account.

CVSS severity8.6
High
EPSS probability0.79%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Local file inclusion in CMSimple 5.4 allows remote authenticated users to execute arbitrary code through a crafted PHP session file. The configuration save path accepts traversal in functions_file, causing CMSimple to include an attacker-controlled PHP session file. Administrative credentials and a valid CSRF token are required; the session-upload payload then runs commands under the web server account.

The record

CVE
CVE-2021-47734
Published
Dec 23, 2025
Updated
Mar 17, 2026
Vendor
CMSimple
Product
CMSimple
Classifications
CWE-98, T1059.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 23, 2025CVE publishedPublication date reported by the CVE source.
  2. Mar 17, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=CMSimple 5.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

CMSimple · CMSimpleversion=CMSimple 5.4

Published CVSS scores

7.8VulnCheckCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.6VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/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.

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-98Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion')
T1059.004Command and Scripting Interpreter: Unix Shell

Public exploit references

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo