CVE intelligence and bounded remediation

CVE-2026-45233 — HTMLy CMS security vulnerability

High CVSS 8.1

HTMLy CMS through 3.1.1 contains a path traversal vulnerability that allows low-privileged authenticated attackers to relocate arbitrary files by supplying directory traversal sequences in the oldfile parameter at the admin autosave endpoint. Attackers can pass unsanitized traversal sequences directly to file_exists() and rename() functions in admin.php without canonicalization or directory boundary enforcement to cause unintended relocation of any file writable by the web server process to an attacker-specified draft location.

Severity
High
CVSS
8.1 (3.1)
Published
2026-06-25
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-22

Affected products

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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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