# Nltk vulnerabilities

Source: https://junglewise.ai/threats/vendors/nltk  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Updated: 9 November 2026, 03:07 UTC. Rebuilt every hour.  
Data: https://junglewise.ai/threats/vendors/nltk.json  
License: CC BY 4.0 with a link back

Junglewise Threat Intelligence has tracked 21 vulnerabilities in Nltk: 0 in the last 7 days and 12 in the last 90 days, 1 of them critical and 0 exploited in the wild. The most recent, NLTK Pl196xCorpusReader quadratic ReDoS on malformed TEI blocks, was published on 27 August 2026. Nothing was published in the last eight weeks. 1 technology has a page of its own.

## Counts

- Last 7 days: 0
- Last 30 days: 0
- Last 90 days: 12
- All time: 21 (1 critical, 0 exploited in the wild)

## About Nltk

Python library for natural language processing tasks including tokenization, stemming, and parsing.

## Latest Nltk vulnerabilities

- [NLTK Pl196xCorpusReader quadratic ReDoS on malformed TEI blocks](https://junglewise.ai/threats/nltk-pl196xcorpusreader-quadratic-redos-on-malformed-tei-blocks-8473e6ef) (low, CVSS 3.7, published 27 Aug 2026)
- [NLTK PorterStemmer quadratic-time DoS via long runs of 'y'](https://junglewise.ai/threats/nltk-porterstemmer-quadratic-time-dos-via-long-runs-of-y-b1fab99a) (high, CVSS 7.5, published 27 Aug 2026)
- [CVE-2026-81725: NLTK Pl196xCorpusReader quadratic ReDoS on malformed TEI blocks](https://junglewise.ai/threats/cve-2026-81725-nltk-pl196xcorpusreader-quadratic-redos-on-malformed-tei-blocks) (medium, CVSS 4, published 27 Aug 2026)
- [CVE-2026-80206: NLTK tgrep regular expression denial of service](https://junglewise.ai/threats/cve-2026-80206-nltk-tgrep-regular-expression-denial-of-service) (high, CVSS 5.9, published 26 Aug 2026)
- [NLTK corpus reader sandbox bypass](https://junglewise.ai/threats/nltk-corpus-reader-sandbox-bypass-6e33487f) (high, CVSS 8.2, published 25 Aug 2026)
- [CVE-2026-79657: NLTK remote code execution via unsafe pickle deserialization](https://junglewise.ai/threats/cve-2026-79657-nltk-remote-code-execution-via-unsafe-pickle-deserialization) (critical, CVSS 9.8, published 25 Aug 2026)
- [NLTK untrusted search path in Graphviz dot invocation](https://junglewise.ai/threats/nltk-untrusted-search-path-in-graphviz-dot-invocation-a4934721) (high, CVSS 7.8, published 25 Aug 2026)
- [CVE-2026-78681: NLTK entity-expansion denial of service via ElementTree parsing](https://junglewise.ai/threats/cve-2026-78681-nltk-entity-expansion-denial-of-service-via-elementtree-parsing) (high, CVSS 7.5, published 25 Aug 2026)
- [CVE-2026-65915: NLTK FileSystemPathPointer sandbox bypass arbitrary file read](https://junglewise.ai/threats/cve-2026-65915-nltk-filesystempathpointer-sandbox-bypass-arbitrary-file-read) (medium, CVSS 6.5, published 22 Aug 2026)
- [CVE-2026-63312: NLTK StreamBackedCorpusView pathsec.ENFORCE bypass](https://junglewise.ai/threats/cve-2026-63312-nltk-streambackedcorpusview-pathsec-enforce-bypass) (high, CVSS 7.5, published 22 Aug 2026)
- [CVE-2026-63310: Rejected reason: This CVE ID has been rejected or withdrawn by its CVE Numbering Authority.](https://junglewise.ai/threats/cve-2026-63310-nltk-missing-post-download-integrity-verification-in-downloader) (high, CVSS 7.1, published 22 Aug 2026)
- [CVE-2026-62384: NLTK FramenetCorpusReader symlink sandbox bypass](https://junglewise.ai/threats/cve-2026-62384-nltk-framenetcorpusreader-symlink-sandbox-bypass) (high, CVSS 7.5, published 22 Aug 2026)
- [CVE-2026-12372: NLTK network URL validation permits SSRF to RFC 6598 shared-address-space hosts](https://junglewise.ai/threats/cve-2026-12372-pysec-2026-3955-a-server-side-request-forgery-ssrf-vulnerability) (low, CVSS 3.7, published 9 Aug 2026)
- [CVE-2026-12259: NLTK missing post-download integrity verification](https://junglewise.ai/threats/cve-2026-12259-nltk-missing-post-download-integrity-verification) (medium, CVSS 6.5, published 3 Aug 2026)
- [CVE-2026-12074: NLTK path traversal in FramenetCorpusReader allows arbitrary XML read](https://junglewise.ai/threats/cve-2026-12074-nltk-path-traversal-in-framenetcorpusreader-allows-arbitrary-xml) (high, CVSS 7.5, published 31 Jul 2026)
- [CVE-2026-12252: NLTK arbitrary code execution in Stanford interface classes](https://junglewise.ai/threats/cve-2026-12252-nltk-arbitrary-code-execution-in-stanford-interface-classes) (high, CVSS 7.8, published 4 Jul 2026)
- [CVE-2026-54293: NLTK path traversal via URL-encoded separators in nltk.data.load](https://junglewise.ai/threats/cve-2026-54293-nltk-path-traversal-via-url-encoded-separators-in-nltk-data-load) (high, CVSS 7.5, published 22 Jun 2026)
- [CVE-2026-33236: NLTK path traversal in downloader component](https://junglewise.ai/threats/cve-2026-33236-nltk-path-traversal-in-downloader-component) (high, CVSS 8.1, published 20 Mar 2026)
- [CVE-2026-33231: NLTK unauthenticated remote shutdown in WordNet Browser](https://junglewise.ai/threats/cve-2026-33231-nltk-unauthenticated-remote-shutdown-in-wordnet-browser) (high, CVSS 7.5, published 20 Mar 2026)
- [CVE-2026-0846: NLTK arbitrary file read in nltk.util.filestring](https://junglewise.ai/threats/cve-2026-0846-nltk-arbitrary-file-read-in-nltk-util-filestring) (high, CVSS 8.6, published 9 Mar 2026)
- [CVE-2021-3828: PYSEC-2021-356 - nltk is vulnerable to Inefficient Regular Expression Complexity](https://junglewise.ai/threats/cve-2021-3828-nltk-redos-in-comparative-sentence-parsing) (low, CVSS 3.1, published 27 Sep 2021)

## Most severe Nltk vulnerabilities

- [CVE-2026-79657: NLTK remote code execution via unsafe pickle deserialization](https://junglewise.ai/threats/cve-2026-79657-nltk-remote-code-execution-via-unsafe-pickle-deserialization) (critical, CVSS 9.8, published 25 Aug 2026)
- [CVE-2026-0846: NLTK arbitrary file read in nltk.util.filestring](https://junglewise.ai/threats/cve-2026-0846-nltk-arbitrary-file-read-in-nltk-util-filestring) (high, CVSS 8.6, published 9 Mar 2026)
- [NLTK corpus reader sandbox bypass](https://junglewise.ai/threats/nltk-corpus-reader-sandbox-bypass-6e33487f) (high, CVSS 8.2, published 25 Aug 2026)
- [CVE-2026-33236: NLTK path traversal in downloader component](https://junglewise.ai/threats/cve-2026-33236-nltk-path-traversal-in-downloader-component) (high, CVSS 8.1, published 20 Mar 2026)
- [CVE-2026-12252: NLTK arbitrary code execution in Stanford interface classes](https://junglewise.ai/threats/cve-2026-12252-nltk-arbitrary-code-execution-in-stanford-interface-classes) (high, CVSS 7.8, published 4 Jul 2026)
- [NLTK untrusted search path in Graphviz dot invocation](https://junglewise.ai/threats/nltk-untrusted-search-path-in-graphviz-dot-invocation-a4934721) (high, CVSS 7.8, published 25 Aug 2026)
- [CVE-2026-33231: NLTK unauthenticated remote shutdown in WordNet Browser](https://junglewise.ai/threats/cve-2026-33231-nltk-unauthenticated-remote-shutdown-in-wordnet-browser) (high, CVSS 7.5, published 20 Mar 2026)
- [CVE-2026-63312: NLTK StreamBackedCorpusView pathsec.ENFORCE bypass](https://junglewise.ai/threats/cve-2026-63312-nltk-streambackedcorpusview-pathsec-enforce-bypass) (high, CVSS 7.5, published 22 Aug 2026)
- [CVE-2026-62384: NLTK FramenetCorpusReader symlink sandbox bypass](https://junglewise.ai/threats/cve-2026-62384-nltk-framenetcorpusreader-symlink-sandbox-bypass) (high, CVSS 7.5, published 22 Aug 2026)
- [CVE-2026-54293: NLTK path traversal via URL-encoded separators in nltk.data.load](https://junglewise.ai/threats/cve-2026-54293-nltk-path-traversal-via-url-encoded-separators-in-nltk-data-load) (high, CVSS 7.5, published 22 Jun 2026)

## Vulnerabilities per week

Nothing was published in the last eight weeks.

| Week of | Vulns | Critical | Exploited |
| --- | --- | --- | --- |
| 17 Aug 2026 | 4 | 0 | 0 |
| 24 Aug 2026 | 8 | 1 | 0 |
| 31 Aug 2026 | 0 | 0 | 0 |
| 7 Sep 2026 | 0 | 0 | 0 |
| 14 Sep 2026 | 0 | 0 | 0 |
| 21 Sep 2026 | 0 | 0 | 0 |
| 28 Sep 2026 | 0 | 0 | 0 |
| 5 Oct 2026 | 0 | 0 | 0 |
| 12 Oct 2026 | 0 | 0 | 0 |
| 19 Oct 2026 | 0 | 0 | 0 |
| 26 Oct 2026 | 0 | 0 | 0 |
| 2 Nov 2026 | 0 | 0 | 0 |
| 9 Nov 2026 | 0 | 0 | 0 |

## Nltk technologies

- [Nltk](https://junglewise.ai/threats/technologies/nltk-nltk): 6 vulnerabilities

## Sources

NVD, GitHub Security Advisories, OSV, the CISA Known Exploited Vulnerabilities catalog, FIRST EPSS and vendor advisories. Rebuilt every hour. Cite as: Junglewise Threat Intelligence, "Nltk vulnerabilities", https://junglewise.ai/threats/vendors/nltk, 9 November 2026.