CVE intelligence and bounded remediation

CVE-2021-23428 — This affects all versions of package elFinder.NetCore

Critical CVSS 9.8

This affects all versions of package elFinder.NetCore. The Path.Combine(...) method is used to create an absolute file path. Due to missing sanitation of the user input and a missing check of the generated path its possible to escape the Files directory via path traversal

Severity
Critical
CVSS
9.8 (3.1)
Published
2021-09-01
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-22

Affected products

  • elfinder.netcore_project / elfinder.netcore

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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