CVE intelligence and bounded remediation
CVE-2017-16941 — Octobercms October security vulnerability
October CMS through 1.0.428 does not prevent use of .htaccess in themes, which allows remote authenticated users to execute arbitrary PHP code by downloading a theme ZIP archive from /backend/cms/themes, and then uploading and importing a modified archive with two new files: a .php file and a .htaccess file. NOTE: the vendor says "I don't think [an attacker able to login to the system under an account that has access to manage/upload themes] is a threat model that we need to be considering.
- Severity
- High
- CVSS
- 8.8 (3.0)
- Published
- 2017-11-25
- CISA KEV
- Not currently listed
- Ecosystem
- software/application
- Weaknesses
- CWE-434
Affected products
- octobercms / october
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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