Tested fixes for CWE-23 in Express, Flask, Spring Boot, ASP.NET Core, Next.js, FastAPI, Django, net/http, Rails and Laravel: the vulnerable code, the fix, a plausible fix that still fails, and the regression tests.
The description above is MITRE’s definition of CWE-23 in CWE 4.20, a base-level weakness.
Common consequences MITRE lists
- Integrity, Confidentiality, Availability: Execute Unauthorized Code or Commands
- Integrity: Modify Files or Directories
- Confidentiality: Read Files or Directories
- Availability: DoS: Crash, Exit, or Restart
Guides on this site
Practice
- Path traversal lab: Keep archive entries inside their extraction directory · Browser lab
- Path traversal lab: Serve an uploaded file without path traversal · Browser lab
- Keep extracted files inside their boundary · Local project
- Convert untrusted documents in a locked-down container · Local project
References
This page is generated from MITRE’s CWE 4.20 catalogue (released 30 April 2026) and lists every guide, fix card and lab here that cites CWE-23.
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