ReviewsCorpusReader extracts feature annotations of the form label followed by a bracketed signed digit (e.g. a label then [+2]) from each review line, using the module-level FEATURES regex. The feature-label sub-pattern is unbounded — an optional greedy run of word-plus-whitespace groups followed by another word, which must then be followed by a literal [. On a long bracket-less line the label can match from every search position to the end …
A path-traversal vulnerability in NKJPCorpusReader allows an attacker who can influence the fileids argument of its public read methods (header, raw, words, sents, tagged_words) to read files outside the corpus root. The reader builds the file path with no containment check and opens it with the builtin open(), so it bypasses NLTK's nltk.pathsec sandbox — including the strict ENFORCE = True mode that SECURITY.md recommends for web/multi-tenant deployments. header() returns …
nltk.pathsec provides an SSRF filter that NLTK documents as a security control, blocking loopback, private, link-local, and multicast ranges (including obfuscated forms) and recommending strict ENFORCE mode for security-sensitive environments. The filter is bypassable by DNS rebinding: validate_network_url() resolves the hostname and checks the resulting IP, but the actual HTTP connection re-resolves the hostname independently at connect time and connects to that second result. The validated IP is never the …
FramenetCorpusReader.frame(name) interpolates a caller-supplied frame name into an XML file path that is read with the builtin open(), bypassing CorpusReader.open() and the nltk.pathsec sandbox — including strict ENFORCE=True mode. A ../ sequence in the name escapes the corpus root, yielding an arbitrary XML file read whose parsed content is returned to the caller.
nltk.data.load() in NLTK is vulnerable to path traversal via URL-encoded path separators and traversal segments when using the nltk: URL scheme. The unsafe-path regex check is performed before url2pathname() decodes the %xx sequences (a classic decode-after-check / TOCTOU-style flaw), allowing an attacker to bypass the protection documented in NLTK's SECURITY.md and read arbitrary files from the filesystem. While literal traversal strings such as ../../../etc/passwd are correctly blocked, encoded variants such …
nltk.app.wordnet_app allows unauthenticated remote shutdown of the local WordNet Browser HTTP server when it is started in its default mode. A simple GET /SHUTDOWN%20THE%20SERVER request causes the process to terminate immediately via os._exit(0), resulting in a denial of service.
Vulnerability Description The NLTK downloader does not validate the subdir and id attributes when processing remote XML index files. Attackers can control a remote XML index server to provide malicious values containing path traversal sequences (such as ../), which can lead to: Arbitrary Directory Creation: Create directories at arbitrary locations in the file system Arbitrary File Creation: Create arbitrary files Arbitrary File Overwrite: Overwrite critical system files (such as /etc/passwd, …
JSONTaggedDecoder.decode_obj() in nltk/jsontags.py calls itself recursively without any depth limit. A deeply nested JSON structure exceeding sys.getrecursionlimit() (default: 1000) will raise an unhandled RecursionError, crashing the Python process.
nltk.app.wordnet_app contains a reflected cross-site scripting issue in the lookup_… route. A crafted lookup_<payload> URL can inject arbitrary HTML/JavaScript into the response page because attacker-controlled word data is reflected into HTML without escaping. This impacts users running the local WordNet Browser server and can lead to script execution in the browser origin of that application.
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 sanitization, enabling attackers to access sensitive system files by providing absolute paths or traversal paths. This vulnerability can be exploited locally or remotely, particularly in scenarios where the function is used in web APIs or …
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 fail to properly sanitize or validate file paths, enabling attackers to traverse directories and access sensitive files on the server. This issue is particularly critical in scenarios where user-controlled file inputs are processed, such as in machine learning APIs, chatbots, or NLP …
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 downloaded packages are trusted and extracts them without validation. If a malicious package contains Python files, …