Reference page — cumulative record through Sunday, October 4, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-63312

CVE-2026-63312HIGH

NLTK StreamBackedCorpusView Bypasses pathsec.ENFORCE Arbitrary File Read

  AV  AC  AT  PR  UI  VC  VI  VA   CVSS    EPSS   %ile   KEV
   N   L   N   N   N   H   N   N    8.7   .0065   49.4     —

AFFECTED
  Product  Versions     Fixed
  nltk     unspecified  3.10.0

TIMELINE
  Jul 16  Reserved by VulnCheck
  Aug 22  Published (CNA: VulnCheck)
  Aug 31  EXPLOIT PUBLISHED — CVE-2026-63312 (nltk). Public exploit reference added.

CWE-22 · CNA: VulnCheck · CVSS v4.0 · 2 references · NVD status: Analyzed

Description

NLTK before 3.10.0 contains an arbitrary local file read vulnerability in StreamBackedCorpusView that bypasses pathsec.ENFORCE by calling builtins.open() directly instead of pathsec.open(). Attackers who control the fileid argument can read arbitrary local files regardless of the ENFORCE setting, including sensitive system files and application credentials.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
July 16, 2026	Reserved	Reserved by VulnCheck
August 22, 2026	Published	Published (CNA: VulnCheck)
August 31, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-63312 (nltk). Public exploit reference added.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
nltk	nltk	—	—	3.10.0

Weaknesses

CWE-22

References (2)

https://github.com/nltk/nltk/security/advisories/GHSA-x5ph-mj9p-rfr8 [Exploit, Vendor Advisory]
https://www.vulncheck.com/advisories/nltk-streambackedcorpusview-bypasses-pathsec-enforce-arbitrary-file-read [Third Party Advisory]

Authoritative record: CVE-2026-63312 at cve.org

Vendors: nltk

Weaknesses: CWE-22

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-63312 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Sunday, October 4, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.