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PatchSiren cyber security CVE debrief

CVE-2021-47943 Exploit Db CVE debrief

CVE-2021-47943 is described in the supplied NVD record as an authenticated remote code execution issue in Textpattern CMS 4.8.7. The core risk is unsafe file upload handling: an authenticated attacker can upload a PHP file through the Files section and then invoke it from the web-accessible files directory to execute commands. The supplied record maps the weakness to CWE-434 (Unrestricted Upload of File with Dangerous Type).

Vendor
Exploit Db
Product
Unknown
CVSS
HIGH 8.7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-10
Original CVE updated
2026-07-25
Advisory published
2026-05-10
Advisory updated
2026-07-25

Who should care

Administrators and security teams running Textpattern CMS 4.8.7 or similar deployments with user-facing file upload capability should review this immediately, especially if non-admin or untrusted authenticated users can upload files.

Technical summary

The supplied description says the application accepts malicious PHP files through its file upload functionality, placing them under /textpattern/files/ where they can be accessed over HTTP. Because the uploaded content is executable, an authenticated attacker may turn a file upload into command execution. The NVD metadata in the corpus associates the issue with CWE-434 and a high-severity CVSS 4.0 vector.

Defensive priority

High. Treat as urgent for any internet-facing or multi-user Textpattern CMS deployment, particularly where upload permissions are broad or upload directories are web-accessible.

Recommended defensive actions

  • Restrict upload permissions so only trusted administrators can add files.
  • Audit the Files section and web-accessible upload directories for unexpected PHP or other executable content.
  • Block server-side execution in upload directories at the web server and PHP configuration layers.
  • Remove or quarantine any uploaded files that should not be executable, and review related access logs for suspicious upload and GET activity.
  • Apply any vendor fix or upgrade guidance referenced by the linked advisories before restoring normal upload access.
  • If uploads are required, enforce allowlists for file type, content validation, and separate storage outside the web root.

Evidence notes

This debrief is based only on the supplied corpus: the NVD record metadata, the user-provided vulnerability description, and the listed reference URLs. The corpus identifies the weakness as CWE-434 and describes authenticated remote code execution via malicious PHP file upload in Textpattern CMS 4.8.7. The reference URLs were not fetched in this environment, so details beyond the supplied summary are intentionally not asserted.

Sources and references

Verified primary and authoritative sources

  • CVE-2021-47943 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2021-47943

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2021-47943 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2021-47943

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.