Is there a public exploit for CVE-2026-12072?

No public exploit for CVE-2026-12072 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-12072?

CVE-2026-12072 scores CVSS 7.5 (v3.1), rated high.

7.5 High

Natural Language Toolkit (NLTK): Path Traversal in NKJPCorpusReader leads to Arbitrary File Read and bypasses the nltk.pathsec sandbox (ENFORCE=True)

CVE-2026-12072

Summary A path-traversal vulnerability in NKJPCorpusReader allows an attacker who can influence the fileids argument of its public read methods (header, raw, words, sents, taggedwords) to read files outside the corpus root. The reader builds the file path with no containment check and opens it with the builtin open(), so it bypasses NLTK's nltk.pathsec sandbox — including the strict ENFORCE = True mode that SECURITY.md recommends for web/multi-tenant deployments. header() returns the parsed content of the out-of-root file to the caller (arbitrary file read). Details SECURITY.md promises that file access is "validated against allowed NLTK data directories" and that with nltk.pathsec.ENFORCE = True "unauthorized file access … will raise PermissionError." That guarantee is enforced via FileSystemPathPointer.open() / CorpusReader.open(), which call nltk.pathsec.validatepath(...). NKJPCorpusReader never uses that protected path. In nltk/corpus/reader/nkjp.py: addroot() builds the path by plain string concatenation with no normalization or containment check: python def addroot(self, fileid): # lines 96-102 if self.root in fileid: return fileid # attacker-controlled value returned…

Assessment

CVSS: 7.5 (v3.1)
Severity: High
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 31 July 2026
Last updated: 31 July 2026
Affected: nltk
Weakness: CWE-22

CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

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