Technology · PyPI
nltk (PyPI) vulnerabilities
Updated . Rebuilt every hour.
Junglewise Threat Intelligence has tracked 74 vulnerabilities in nltk (PyPI): 0 in the last 7 days and 67 in the last 90 days, 7 of them critical and 0 exploited in the wild. The most recent, CVE-2026-12259, was published on 8 September 2026.
- Last 7 days
- 0
- Last 90 days
- 67
- Critical, all time
- 7
- Exploited in the wild
- 0
About nltk (PyPI)
A suite of libraries and programs for symbolic and statistical natural language processing for the Python programming language.
Latest nltk (PyPI) vulnerabilities
- CVE-2026-12259: NLTK missing post-download integrity verificationmediumCVSS 5.3EPSS 0.1%
- CVE-2026-12876: NLTK RecursiveDescentParser uncontrolled recursion denial of servicemediumCVSS 4
- NLTK tgrep regular expression denial of servicemediumCVSS 5.9
- NLTK uncontrolled recursion in FeatStructReader denial of servicemediumCVSS 5.3
- NLTK Downloader hardlink filesystem containment bypasshighCVSS 7.1
- NLTK Pl196xCorpusReader quadratic ReDoS on malformed TEI blockslowCVSS 3.7
- NLTK path traversal in model-artifact APIs via pathsec bypasshighCVSS 7
- NLTK PorterStemmer quadratic-time DoS via long runs of 'y'highCVSS 7.5
- NLTK quadratic CPU exhaustion in XMLCorpusView._read_xml_fragment()lowCVSS 3.7
- CVE-2026-81727: NLTK versions before 3.10.3 contain a filesystem containment bypass vulnerability in the Downloader.download and…highCVSS 7.1EPSS 0.2%
- CVE-2026-81726: NLTK through 3.10.3 contains a path traversal vulnerability in model-artifact APIs that bypass pathsec enforcement by…highCVSS 7EPSS 0.3%
- CVE-2026-81725: NLTK before 3.10.3 contains a regular expression denial of service vulnerability in Pl196xCorpusReader that allows…mediumCVSS 4EPSS 0.4%
- CVE-2026-81724: NLTK before 3.10.3 contains an uncontrolled recursion vulnerability in nltk.featstruct.FeatStructReader that allows…mediumCVSS 5.3EPSS 0.5%
- CVE-2026-81723: NLTK versions before 3.10.3 contain a quadratic CPU exhaustion vulnerability in XMLCorpusView._read_xml_fragment() that…lowCVSS 3.7EPSS 0.4%
- CVE-2026-81722: nltk PorterStemmer in versions <= 3.10.2 (fixed in 3.10.3) contains an inefficient-algorithmic-complexity denial of…highCVSS 7.5EPSS 0.5%
- NLTK ReDoS in Text.findall() via unvalidated regexhighCVSS 7.5
- NLTK ReDoS in Text.findall() via unvalidated regular expressionslowCVSS 3.1
- CVE-2026-80206: NLTK before 3.10.3 contains a regular expression denial of service (ReDoS) vulnerability in the tgrep module. The…highCVSS 5.9EPSS 0.4%
- CVE-2026-80205: NLTK versions before 3.10.0 contain a regular expression denial of service vulnerability in Text.findall() and…highCVSS 7.5EPSS 0.7%
- NLTK corpus reader sandbox bypasshighCVSS 8.2
- NLTK corpus readers symlink path traversal bypassmediumCVSS 5.9
- NLTK JVM argument injection bypass in Stanford wrapperslowCVSS 3.1
- NLTK JVM argument injection in Stanford wrappers via per-call optionscriticalCVSS 9.8
- CVE-2026-79676: NLTK versions before 3.10.3 contain a path traversal vulnerability in corpus readers that reopen root-derived paths using…highCVSS 5.9EPSS 0.4%
- CVE-2026-79675: NLTK before 3.10.3 fails to validate JVM options passed through the per-call options parameter in the java() function…criticalCVSS 9.8EPSS 0.8%
Most severe nltk (PyPI) vulnerabilities
Exploited in the wild first, then by severity and CVSS score.
- CVE-2025-14009: NLTK Zip Slip remote code execution in downloader componentcriticalCVSS 10EPSS 0.9%
- CVE-2026-79657: NLTK versions before 3.10.3 contain a remote code execution vulnerability in allowlisted pickle loaders that trust entire…criticalCVSS 9.8EPSS 1.3%
- CVE-2026-79675: NLTK before 3.10.3 fails to validate JVM options passed through the per-call options parameter in the java() function…criticalCVSS 9.8EPSS 0.8%
- NLTK JVM argument injection in Stanford wrappers via per-call optionscriticalCVSS 9.8
- NLTK unsafe pickle deserialization in allowlisted loaderscriticalCVSS 9.8
- CVE-2026-78683: NLTK before 3.10.0 (affected versions <=3.9.4) contains an unsafe pickle deserialization vulnerability in the…criticalCVSS 9.6EPSS 0.5%
- NLTK unsafe pickle deserialization in TransitionParsercriticalCVSS 9.6
- CVE-2026-71513: NLTK before 3.10.3 contains a remote code execution vulnerability in AllowlistUnpickler that validates only the pickle…highCVSS 8.8EPSS 1.1%
- CVE-2026-0847: NLTK path traversal in CorpusReader classeshighCVSS 8.6EPSS 0.9%
- CVE-2026-0846: NLTK arbitrary file read in nltk.util.filestringhighCVSS 8.6EPSS 0.5%
Vulnerabilities per week
The last 13 weeks, by the week each vulnerability was published.
| Week of | Bar | Vulns | Critical |
|---|---|---|---|
| 29 Jun 2026 | 3 | 0 | |
| 6 Jul 2026 | 0 | 0 | |
| 13 Jul 2026 | 0 | 0 | |
| 20 Jul 2026 | 1 | 0 | |
| 27 Jul 2026 | 4 | 0 | |
| 3 Aug 2026 | 1 | 0 | |
| 10 Aug 2026 | 0 | 0 | |
| 17 Aug 2026 | 22 | 0 | |
| 24 Aug 2026 | 33 | 6 | |
| 31 Aug 2026 | 2 | 0 | |
| 7 Sep 2026 | 1 | 0 | |
| 14 Sep 2026 | 0 | 0 | |
| 21 Sep 2026 | 0 | 0 |
How this is built
Junglewise Threat Intelligence collects vulnerabilities from NVD, GitHub Security Advisories, OSV, the CISA Known Exploited Vulnerabilities catalog, FIRST EPSS and vendor advisories, and matches each one to the technologies and vendors it affects. Dates are the date a vulnerability was published, in UTC.
The pages are rebuilt from the database every hour. Frozen weekly and monthly reports never change once published, so they can be cited.
Use this data
The same data is at https://junglewise.ai/threats/technologies/nltk.json, for scripts and language models. It is free to reuse under CC BY 4.0 with a link back to this page.
Cite as: Junglewise Threat Intelligence, "nltk (PyPI) vulnerabilities", https://junglewise.ai/threats/technologies/nltk, 26 September 2026.