NLTK: StreamBackedCorpusView Bypasses pathsec.ENFORCE - Arbitrary Local File Read
Published Aug 22, 2026 · Updated Nov 3, 2026
Original summary
Normalized public record · Updated Nov 3, 2026
NLTK: StreamBackedCorpusView Bypasses pathsec.ENFORCE - Arbitrary Local File Read
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
## Summary Setting `nltk.pathsec.ENFORCE = True` is documented to sandbox all file access to allowed NLTK data directories and raise `PermissionError` on unauthorized access. However, `StreamBackedCorpusView` opens files via `builtins.open()` directly, bypassing `pathsec.validate_path()` entirely. An attacker who can influence the `fileid` argument can read arbitrary local files regardless of the `ENFORCE` setting.
Evidence: public source recordsAffected products
| Affected package, product or range | Fix status |
|---|---|
| Consult the referenced vendor advisory for affected versions. | Consult source advisory |
Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.
Remediation
Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.
- Confirm the affected product and reachable code path exist in your environment.
- Apply the vendor-supported patch or mitigation from the primary advisory.
- Rescan the exact deployed revision and retain verification evidence.
Evidence coverage
- SSVC priority
- MEDIUM
- Confidence
- Not available
- Aliases
- None reported
Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.
Sources and record history
- Security advisory ↗
- VulnCheck Advisory: NLTK StreamBackedCorpusView Bypasses pathsec.ENFORCE Arbitrary File Read ↗
Record history
Published Aug 22, 2026 · Last refreshed Nov 3, 2026