nltk has 36 CVEs on record between 2022 and 2026. Disclosure cadence is accelerating: 27 in the last 90 days against 1 in the 90 before. The busiest recent month was August 2026 with 16. The median CVSS is 7.5 (high), with 2 rated critical. None have a confirmed exploitation report. The dominant weakness classes are CWE-22 (11) and CWE-1333 (4). Most affected products: nltk (34), nltk/nltk (2).
CVEs per month
Last 12 months, by publish date
- Exploited share
- 0% vs 1% corpus
- Median CVSS
- 7.5
- Publish → KEV
- —
- Last 90 days
- 27 prev 1
Weakness classes
Products
- nltk 34
- nltk/nltk 2
Worst active — by depth score
CVE-2026-0846High· 8.6Arbitrary File Read via Absolute Path Input in nltk.util.filestring()59CVE-2026-0847High· 8.6Path Traversal in nltk/nltk59CVE-2026-33231High· 7.5NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing54CVE-2026-79657CriticalNLTK: Allowlisted pickle loaders still permit code execution in current source53CVE-2026-72818High· 7.5The URLS regular expression in nltk/tokenize/casual.py, compiled into TweetTokenizer.WORD_RE and applied by TweetTokenizer.tokenize, contains a naked-domain branch whose domain-label prefix [a-z0-9]+(?:[.\-][a-z0-9]+)* is unbounded53
nltk vulnerabilities
CVEs affecting nltk, newest first. Open any entry for full detail, references, and exploit status.
36 CVEsRSS
CVE-2026-33230Medium· 6.1Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in nltk
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in nltk
CVE-2026-0846High· 8.6PoCArbitrary File Read via Absolute Path Input in nltk.util.filestring()
A vulnerability in the `filestring()` function of the `nltk.util` module in nltk version 3.9.2 allows arbitrary file read due to improper validation of input paths. The function directly opens files specified by user input without saniti…
CVE-2026-0847High· 8.6PoCPath Traversal in nltk/nltk
A vulnerability in NLTK versions up to and including 3.9.2 allows arbitrary file read via path traversal in multiple CorpusReader classes, including WordListCorpusReader, TaggedCorpusReader, and BracketParseCorpusReader. These classes fa…
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)