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Vulnerabilities

Vulnerability · CVE-2026-81726

NLTK: WekaClassifier passes an unvalidated caller-controlled model path to the weka JVM, bypassing nltk.pathsec containment

Published Oct 27, 2026 · NLTK: WekaClassifier passes an

Last checked Nov 6, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-81726. EPSS is 0.34%. Act only if a listed version of NLTK: WekaClassifier passes an is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (NLTK: WekaClassifier passes an).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Unknown—
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.34%
Remediation
Not established
Affected products
pypi nltk

WekaClassifier in NLTK passes a caller-controlled model file path to the weka Java VM without any nltk.pathsec validation. WekaClassifier.train puts the caller's model_filename verbatim into the weka argv ["-d", model_filename, …] (weka writes the trained model there), and WekaClassifier._classify_many puts self._model into ["-l", self._model, …] (weka reads it). Under nltk.pathsec.ENFORCE=True (the default on current HEAD), NLTK's stated invariant — established by advisory CVE-2026-81726 / GHSA-8mgp-746c-j5xp — is that caller-controlled model-artifact …

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • pypi nltkversion unspecified

How to fix CVE-2026-81726

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-81726. EPSS is 0.34%. Act only if a listed version of NLTK: WekaClassifier passes an is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.34%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 27, 2026 · GitLab Advisory Database

    Detected

    WekaClassifier in NLTK passes a caller-controlled model file path to the weka Java VM without any nltk.pathsec validation. WekaClassifier.train puts the caller's model_filename verbatim into the weka argv ["-d", model_filename, …] (weka writes the trained model there), and WekaClassifier._classify_many puts self._model into ["-l", self._model, …] (weka reads it). Under nltk.pathsec.E

Sources

  • CVE.orgVulnerability recordCVE-2026-81726

    Official CVE identifier

    cve.org
  • GitLab Advisory DatabasePackage advisoryCVE-2026-81726

    WekaClassifier in NLTK passes a caller-controlled model file path to the weka Java VM without any nltk.pathsec validation. WekaClassifier.train puts the caller's model_filename verbatim into the weka argv ["-d", model_filename, …] (weka writes the trained model there), and WekaClassifier._classify_many puts self._model into ["-l", self._model, …] (weka reads it). Under nltk.pathsec.E

    advisories.gitlab.com

Freshness

Last verified in this catalog Nov 6, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgOct 28, 2026
  • GitLab Advisory DatabaseOct 28, 2026