CVE-2021-47976Public exploitNetwork attack vector

Authenticated code execution via executable plugin upload

Published May 16, 2026 · Updated May 16, 2026

Remote code execution in Textpattern CMS 4.9.0-dev allows remote authenticated users to execute PHP via a crafted plugin upload. The plugin_upload action accepts a .php file in the theplugin field and writes it beneath the web-accessible textpattern/tmp directory without blocking executable content. An account with access to the Plugins panel can obtain the request token and place a web shell whose commands run with the web server's privileges.

CVSS severity8.7
High
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Remote code execution in Textpattern CMS 4.9.0-dev allows remote authenticated users to execute PHP via a crafted plugin upload. The plugin_upload action accepts a .php file in the theplugin field and writes it beneath the web-accessible textpattern/tmp directory without blocking executable content. An account with access to the Plugins panel can obtain the request token and place a web shell whose commands run with the web server's privileges.

The record

CVE
CVE-2021-47976
Published
May 16, 2026
Updated
May 16, 2026
Vendor
Textpattern
Product
Textpattern CMS
Classifications
CWE-352, T1190, T1505.003
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 16, 2026CVE publishedPublication date reported by the CVE source.
  2. May 16, 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=4.9.0-dev

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Textpattern · Textpattern CMSversion=4.9.0-dev

Published CVSS scores

8.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
8.8VulnCheckCVSS:3.1/AV:N/AC:L/PR:L/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.

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-352Cross-Site Request Forgery (CSRF)
T1190Exploit Public-Facing Application
T1505.003Server Software Component: Web Shell

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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