CVE intelligence and bounded remediation

CVE-2018-9109 — Std42 Elfinder security vulnerability

Critical CVSS 9.1

Studio 42 elFinder before 2.1.36 has a directory traversal vulnerability in elFinder.class.php with the zipdl() function that can allow a remote attacker to download files accessible by the web server process and delete files owned by the account running the web server process.

Severity
Critical
CVSS
9.1 (3.1)
Published
2018-03-28
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-22

Affected products

  • std42 / elfinder

Matched remediation archetype

Path traversal, unsafe upload, and file handling

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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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