nltk has 39 CVEs on record between 2022 and 2026. Disclosure cadence is accelerating: 24 in the last 90 days against 9 in the 90 before. The busiest recent month was August 2026 with 23. The median CVSS is 7.5 (high), with 2 rated critical. None have a confirmed exploitation report. The dominant weakness classes are CWE-22 (14) and CWE-59 (4).
CVEs per month
Last 12 months, by publish date
- Exploited share
- 0% vs 1% corpus
- Median CVSS
- 7.5
- Publish → KEV
- —
- Last 90 days
- 24 prev 9
Weakness classes
Products
- nltk 39
Worst active — by depth score
CVE-2026-79657Critical· 9.8NLTK versions before 3.10.3 contain a remote code execution vulnerability in allowlisted pickle loaders that trust entire module namespaces instead of specific safe callables66CVE-2026-0847High· 8.6NLTK has a Path Traversal issue60CVE-2025-71408High· 7.8NLTK (Natural Language Toolkit) before version 3.9.3 contains an eval injection vulnerability in the nltk.collocations module that allows an attacker who controls command-line arguments to execute arbitrary Python code55CVE-2026-78683Critical· 9.6NLTK before 3.10.0 (affected versions <=3.9.4) contains an unsafe pickle deserialization vulnerability in the TransitionParser.parse() method (nltk/parse/transitionparser.py)53CVE-2026-78682High· 7.5NLTK before 3.10.3 contains a server-side request forgery vulnerability in nltk.pathsec.urlopen (and callers nltk.data.load, nltk.downloader.Downloader.index/download) when an HTTP proxy is configured53
nltk vulnerabilities
CVEs affecting nltk, newest first. Open any entry for full detail, references, and exploit status.
39 CVEsRSS
CVE-2025-71408High· 7.8PoCNLTK (Natural Language Toolkit) before version 3.9.3 contains an eval injection vulnerability in the nltk.collocations module that allows an attacker who controls command-line arguments to execute arbitrary Python code
NLTK (Natural Language Toolkit) before version 3.9.3 contains an eval injection vulnerability in the nltk.collocations module that allows an attacker who controls command-line arguments to execute arbitrary Python code. When collocations…
CVE-2026-12252High· 7.8In nltk/nltk versions 3.9.3 and earlier, five Stanford interface classes (StanfordPOSTagger, StanfordNERTagger, StanfordParser, StanfordDependencyParser, and StanfordNeuralDependencyParser) are vulnerable to untrusted JAR code execution.…
In nltk/nltk versions 3.9.3 and earlier, five Stanford interface classes (StanfordPOSTagger, StanfordNERTagger, StanfordParser, StanfordDependencyParser, and StanfordNeuralDependencyParser) are vulnerable to untrusted JAR code execution.…
CVE-2026-54293High· 7.5PoCNLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing
NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing. Prior to 3.10.0-rc1, nltk.data.load() in NLTK is vulnerable to path tr…
CVE-2026-33236High· 8.1NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing
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, the NLTK downloader does not validate the…
CVE-2026-33231High· 7.5PoCNLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing
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, `nltk.app.wordnet_app` allows unauthentic…
CVE-2026-0847High· 8.6PoCNLTK has a Path Traversal issue
NLTK has a Path Traversal issue
CVE-2025-14009High· 8.8A critical vulnerability exists in the NLTK downloader component of nltk/nltk, affecting all versions
A critical vulnerability exists in the NLTK downloader component of nltk/nltk, affecting all versions. The _unzip_iter function in nltk/downloader.py uses zipfile.extractall() without performing path validation or security checks. This a…
CVE-2024-39705High· 7.5ntlk unsafe deserialization vulnerability
ntlk unsafe deserialization vulnerability
CVE-2021-43854High· 7.5Inefficient Regular Expression Complexity in nltk (word_tokenize, sent_tokenize)
Inefficient Regular Expression Complexity in nltk (word_tokenize, sent_tokenize)