CVE-2021-47753Public exploitNetwork attack vector

Remote code execution via upload rename bypass

Published Jan 15, 2026 · Updated Jan 15, 2026

Unrestricted file upload in phpKF CMS 3.00 Beta y6 allows remote attackers to execute arbitrary code through a crafted image upload. The /phpkf-bilesenler/yukleme/index.php endpoint accepts PHP content named as a PNG and then honors a yenidenadlandir request that changes its suffix to .php. Public self-registration supplies the session cookie required by the upload and rename requests, after which the uploaded web shell executes system commands.

CVSS severity9.3
Critical
EPSS probability0.76%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unrestricted file upload in phpKF CMS 3.00 Beta y6 allows remote attackers to execute arbitrary code through a crafted image upload. The /phpkf-bilesenler/yukleme/index.php endpoint accepts PHP content named as a PNG and then honors a yenidenadlandir request that changes its suffix to .php. Public self-registration supplies the session cookie required by the upload and rename requests, after which the uploaded web shell executes system commands.

The record

CVE
CVE-2021-47753
Published
Jan 15, 2026
Updated
Jan 15, 2026
Vendor
phpKF
Product
phpKF CMS
Classifications
CWE-434, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 15, 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?

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

  1. Affected versionversion=3.00

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

phpKF · phpKF CMSversion=3.00

Published CVSS scores

9.8VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.3VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/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.

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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-434Unrestricted Upload of File with Dangerous Type
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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