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A Server-Side Request Forgery (SSRF) vulnerability exists in nltk/nltk versions 3.9.4 and the current develop branch. The `nltk.pathsec.validate_network_url()` function, intended to prevent SSRF by rejecting internal network addresses, fails to reject IPs in the RFC 6598 shared address space (`100.64.0.0/10`). This occurs because Python's `ipaddress` module does not classify such addresses as `is_private` [truncated]
The CVE record for CVE-2026-12259 was published on 2026-08-03T08:17:17.880Z and has not been modified since then. The NVD entry is currently Received. This vulnerability affects nltk version 3.9.4, allowing attackers to tamper with package responses, potentially leading to malicious package installation. The vulnerability can be exploited through a compromised mirror, malicious proxy, or other source-subs [truncated]
CVE-2026-12252 is a high-severity vulnerability (CVSS Score: 7.8) affecting nltk/nltk versions 3.9.3 and earlier. The vulnerability exists in five Stanford interface classes: StanfordPOSTagger, StanfordNERTagger, StanfordParser, StanfordDependencyParser, and StanfordNeuralDependencyParser. These classes accept user-controllable JAR paths and execute them via the `java()` function, which invokes `subproces [truncated]
CVE-2026-54293 is a high-severity path traversal vulnerability in the NLTK library. Prior to version 3.10.0-rc1, the nltk.data.load() function is vulnerable to path traversal attacks via URL-encoded path separators and traversal segments when using the nltk: URL scheme. This flaw allows an attacker to bypass security protections and read arbitrary files from the filesystem. The vulnerability is fixed in v [truncated]
A vulnerability in `nltk.app.wordnet_app` up to version 3.9.3 allows unauthenticated remote shutdown of the local WordNet Browser HTTP server when started in its default mode. The server listens on all interfaces and processes a specific unauthenticated GET request to terminate the process immediately via `os._exit(0)`. This results in a denial of service, impacting service availability. The issue arises [truncated]
CVE-2026-33236 is a high-severity vulnerability in the Natural Language Toolkit (NLTK) that allows attackers to perform path traversal attacks. The vulnerability exists in versions 3.9.3 and prior, where the NLTK downloader fails to validate the `subdir` and `id` attributes when processing remote XML index files. This allows attackers to control a remote XML index server and provide malicious values conta [truncated]
CVE-2026-33231 is a high-severity denial of service vulnerability in the Natural Language Toolkit (NLTK) library, specifically affecting the wordnet_app feature in versions 3.9.3 and prior. An unauthenticated remote attacker can cause the local WordNet Browser HTTP server to shut down immediately by sending a specially crafted GET request. This vulnerability has been patched in a recent commit. Users shou [truncated]
CVE-2026-0846 is a high-severity vulnerability in the NLTK library's `filestring()` function, which allows for arbitrary file reads due to improper validation of input paths. The function directly opens files specified by user input without sanitization, enabling attackers to access sensitive system files by providing absolute paths or traversal paths. This vulnerability can be exploited locally or remote [truncated]
CVE-2026-0847 is a high-severity vulnerability in the Natural Language Toolkit (NLTK) library, affecting versions up to and including 3.9.2. The vulnerability is caused by multiple CorpusReader classes, including WordListCorpusReader, TaggedCorpusReader, and BracketParseCorpusReader, failing to properly sanitize or validate file paths. This allows attackers to traverse directories and access sensitive fil [truncated]
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 allows attackers to craft malicious zip packages that, when downloaded and extracted by NLTK, can execute arbitrary code. The vulnerability arises because NLTK assumes all [truncated]