CVE-2026-81726

A flaw was found in NLTK. This vulnerability, known as path traversal, allows an attacker to bypass security restrictions in the model-artifact APIs. By exploiting this, an attacker can perform unauthorized read or write operations on files outside the intended secure directories. This could lead...

CVE-2026-81725

A flaw was found in NLTK, specifically within the Pl196xCorpusReader component. A remote attacker can exploit this by supplying malformed Text Encoding Initiative TEI blocks containing numerous unmatched opening tags. This triggers a regular expression denial of service ReDoS vulnerability, causi...

CVE-2026-81724

A flaw was found in NLTK. This uncontrolled recursion vulnerability in nltk.featstruct.FeatStructReader allows unauthenticated attackers to cause a denial of service. Attackers can achieve this by supplying deeply nested feature-structure input, which can lead to applications crashing when parsin...

CVE-2026-81722

A flaw was found in the nltk PorterStemmer component. A remote attacker could exploit this vulnerability by providing a specially crafted, untrusted token. The inefficient algorithmic complexity in the stemming process, specifically within the isconsonant and measure helper functions, causes...

The vulnerability of the application software interface of the Natural Language Processing library package NLTK allows a hacker to bypass existing security mechanisms and gain access to read and write arbitrary files.

The vulnerability of the application programming interface of the Natural Language Processing library NLTK is related to improper external management of file names or file paths. Exploiting this vulnerability can allow an attacker to bypass existing security mechanisms and gain read-write access ...

The vulnerability of the `nltk.downloader.Downloader.download` and `nltk.downloader.Downloader.incr_download` components of the NLTK library, which are used for symbolic and statistical processing of natural language, allows attackers to bypass existing security mechanisms and gain access to write and delete any files they desire.

The vulnerability of the nltk.downloader.Downloader.download and nltk.downloader.Downloader.incrdownload components of the NLTK library, which are used for symbolic and statistical processing of natural language, is related to an incorrect definition of symbolic references before accessing files...

Duplicate Advisory: ReDoS in nltk.tgrep via unvalidated user-supplied regular expressions

Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-w3v8-gmh9-3wv7. This link is maintained to preserve external references. Original Description NLTK before 3.10.3 contains a regular expression denial of service ReDoS vulnerability in the tgrep module. The...

GHSA-VF76-F5CP-9846 Duplicate Advisory: ReDoS in nltk.tgrep via unvalidated user-supplied regular expressions

Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-w3v8-gmh9-3wv7. This link is maintained to preserve external references. Original Description NLTK before 3.10.3 contains a regular expression denial of service ReDoS vulnerability in the tgrep module. The...

SUSE CVE-2026-66393

NLTK versions before 3.9.4 contain an unbounded recursion vulnerability in JSONTaggedDecoder.decodeobj that allows attackers to cause denial of service by supplying deeply nested JSON structures. Attackers can craft JSON payloads exceeding the recursion limit to trigger an unhandled RecursionErro...

SUSE CVE-2026-70626

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 resolution, enabling attackers to place...

CVE-2026-63312

A flaw was found in NLTK. This vulnerability, specifically within the StreamBackedCorpusView component, allows an attacker to bypass security enforcement by directly calling builtins.open instead of the intended pathsec.open. By controlling the fileid argument, an attacker can read arbitrary loca...

CVE-2026-71514

A flaw was found in NLTK. This path traversal vulnerability in the CrubadanCorpusReader component allows an attacker, who controls a corpus package, to disclose file contents outside the intended corpus directory. This occurs because a specially crafted input can bypass security checks, leading t...

CVE-2026-62385

A flaw was found in NLTK. This path traversal vulnerability, located in the FramenetCorpusReader and NKJPCorpusReader components, allows an attacker to read arbitrary XML files accessible to the application. This can be achieved by supplying unsafe selectors or poisoned index state, exploiting...

CVE-2026-62383

A flaw was found in nltk. A local attacker can exploit a symlink-based vulnerability in the IPIPANCorpusReader methods. By placing a symbolic link in the corpus root directory and invoking specific methods, an attacker can bypass security validation and read arbitrary files accessible to the...

CVE-2026-72818

A flaw was found in NLTK. The TweetTokenizer component, used for processing social media text, contains a regular expression vulnerability. A remote unauthenticated attacker can provide specially crafted input containing many alternating label separators, causing the regular expression to backtra...

CVE-2026-71513

A flaw was found in NLTK. A remote attacker can achieve remote code execution by crafting untrusted transition-parser models. This vulnerability exists in the AllowlistUnpickler, which incorrectly validates only the pickle module string and not the global name. This allows attackers to bypass the...

CVE-2026-62388

A flaw was found in NLTK. The software's default settings in pathsec.py cause security checks to only issue warnings rather than actively preventing malicious actions. This allows attackers to bypass safeguards designed to prevent unauthorized access to files path traversal and the execution of...

CVE-2026-70626

A flaw was found in NLTK. This vulnerability allows a local attacker to read arbitrary files outside of the intended directory. By placing symbolic links symlinks within the corpus root, an attacker can bypass path validation in the CorpusReader.open function, which does not properly account for...

CVE-2026-66393

A flaw was found in NLTK. A remote attacker can exploit an unbounded recursion vulnerability in the JSONTaggedDecoder.decodeobj function by supplying deeply nested JSON structures. This can cause the Python process to crash, leading to a denial of service. Mitigation To mitigate this vulnerabilit...

PT-2026-89701

Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-w3v8-gmh9-3wv7. This link is maintained to preserve external references. Original Description NLTK before 3.10.3 contains a regular expression denial of service ReDoS vulnerability in the tgrep module. The tgrep...