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nltk

45 known vulnerabilities.

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  • Medium 5.3

    NLTK before 3.10.3 Denial of Service via Uncontrolled Recursion

    NLTK before 3.10.3 contains an uncontrolled recursion vulnerability in nltk.featstruct.FeatStructReader that allows unauthenticated attackers to cause a denial of service by supplying deeply nested feature-structure input. Attackers can craft trivial payloads…

  • Medium 5.9

    NLTK 3.10.2 Regular Expression Denial of Service via tgrep

    NLTK before 3.10.3 contains a regular expression denial of service (ReDoS) vulnerability in the tgrep module. The _tgrep_node_action function compiles user-supplied regular expressions embedded in /regex/ pattern nodes and executes them via re.search against …

  • Medium 5.9

    NLTK before 3.10.3 Path Traversal via Symlink Bypass

    NLTK versions before 3.10.3 contain a path traversal vulnerability in corpus readers that reopen root-derived paths using built-in open() instead of nltk.pathsec.open(), allowing symlinks to escape trusted roots. Attackers who stage symlinked corpus files und…

  • Medium 6.2

    NLTK before 3.9.4 Symlink Escape via CorpusReader

    NLTK versions before 3.9.4 contain a symlink escape vulnerability in CorpusReader.open() that allows local attackers to read arbitrary files outside the corpus root. The vulnerability exists because path validation is lexical and does not account for symlink …

  • Medium 6.5

    NLTK before 3.10.0 Arbitrary File Read via FileSystemPathPointer

    NLTK versions before 3.10.0 contain a logic bug in FileSystemPathPointer.open() where the sandbox validation check compares a normalized path against itself, making the security check permanently inert. Attackers can pass file:// URLs to nltk.data.load() to r…

  • Medium 5.3

    NLTK before 3.10.0 SSRF via DNS Resolution Failure

    NLTK before 3.10.0 (affected versions <= 3.9.4) contains a server-side request forgery (SSRF) vulnerability in the validate_network_url() function in nltk/pathsec.py. The _resolve_hostname() helper catches OSError and ValueError during socket.getaddrinfo() an…

  • Medium 5.9

    NLTK 3.9.4 Path Traversal via FrameNet and NKJP Readers

    NLTK versions before 3.10.0 contain a path traversal vulnerability in FramenetCorpusReader and NKJPCorpusReader that allows attackers to parse XML files outside the corpus root by supplying unsafe selectors or poisoned index state. Attackers can exploit frame…

  • Medium 5.5

    nltk IPIPANCorpusReader Symlink Arbitrary File Read

    nltk versions before 3.10.2 contain a symlink-based arbitrary file read vulnerability in IPIPANCorpusReader methods that bypass nltk.pathsec validation entirely. Attackers can place a symlink in the corpus root directory and read arbitrary files accessible to…

  • Medium 5.3

    Improper Access Control in nltk/nltk

    A vulnerability in `nltk.downloader` in nltk/nltk versions <= 3.9.4 allows for cross-package resource and model poisoning. The downloader extracts package archives into shared namespaces such as `corpora/` and `taggers/` instead of package-isolated roots, and…

  • Medium 5.3

    Improper Input Validation in nltk/nltk

    In nltk version 3.9.4, the `nltk.downloader.Downloader._download_package()` function writes downloaded package bytes to disk and may extract them before enforcing SHA-256 or MD5 checksum validation. This allows an attacker to tamper with the package response …

  • Medium 6.1

    nltk Vulnerable to Cross-site Scripting

    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` contains a reflected cross-site scriptin…