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Vulnerabilities

Vulnerability · CVE-2026-33231

NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing.

Published Mar 20, 2026 · catalog updated Sep 9, 2026 · NLTK (Natural Language Toolkit)

Check if you run it

No confirmed exploitation is on record for CVE-2026-33231. EPSS is 1.52%. Act only if a listed version of NLTK (Natural Language Toolkit) 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 (Natural Language Toolkit)).
  • 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
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
1.52%
Remediation
Advisory link
Affected products
cpe nltk/nltk

NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing. In versions 3.9.3 and prior, allows unauthenticated remote shutdown of the local WordNet Browser HTTP server when it is started in its default mode. A simple request causes the process to terminate immediately via , resulting in a denial of service. Commit bbaae83db86a0f49e00f5b0db44a7254c268de9b patches the issue.

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.

  • cpe nltk/nltkversion unspecified

How to fix CVE-2026-33231

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-2026-33231. EPSS is 1.52%. Act only if a listed version of NLTK (Natural Language Toolkit) 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?

CWE-306: Missing Authentication for Critical Function. EPSS 1.52%. 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. Mar 20, 2026 · NIST NVD

    Detected

    NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing. In versions 3.9.3 and prior, allows unauthenticated remote shutdown of the local WordNet Browser HTTP server when it is started in its default mode. A simple request causes the process to terminate immediately via , resulting in a de

  2. Sep 9, 2026 · NIST NVD

    Updated

    NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing. In versions 3.9.3 and prior, allows unauthenticated remote shutdown of the local WordNet Browser HTTP server when it is started in its default mode. A simple request causes the process to terminate immediately via , resulting in a de

Sources

  • CVE.orgVulnerability recordCVE-2026-33231

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-33231

    30-day exploitation probability 1.5%

    first.org
  • NIST NVDVulnerability recordCVE-2026-33231

    NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing. In versions 3.9.3 and prior, allows unauthenticated remote shutdown of the local WordNet B

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.