CVE intelligence and bounded remediation

CVE-2021-37770 — Nucleus CMS v3.71 is affected by a file upload vulnerability

High CVSS 7.2

Nucleus CMS v3.71 is affected by a file upload vulnerability. In this vulnerability, we can use upload to change the upload path to the path without the Htaccess file. Upload an Htaccess file and write it to AddType application / x-httpd-php.jpg. In this way, an attacker can upload a picture with shell, treat it as PHP, execute commands, so as to take down website resources.

Severity
High
CVSS
7.2 (3.1)
Published
2022-06-30
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-434

Affected products

  • nucleuscms / nucleus_cms / 3.71

Matched remediation archetype

Path traversal, unsafe upload, and file handling

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace untrusted filenames, archive entries, URLs, and path segments into read, write, include, extraction, and upload operations.
  • Identify filesystem roots, mount permissions, symbolic-link behavior, archive handling, and whether uploaded content is web-accessible or executable.
  • Review canonicalization and containment checks across supported operating systems and storage backends.

Remediate safely

  • Generate server-side storage identifiers and resolve paths beneath a fixed root using filesystem-aware containment checks.
  • Reject absolute, parent-relative, alternate-separator, device, link, and archive entries that escape the intended root.
  • Store uploads outside executable or served paths, validate type and size, and use private atomic temporary files.

Authoritative sources

Complete CVE record and remediation plan

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