VulnSea

nltk has 36 CVEs on record between 2022 and 2026. Disclosure cadence is accelerating: 27 in the last 90 days against 1 in the 90 before. The busiest recent month was August 2026 with 14. The median CVSS is 7.5 (high), with 2 rated critical. None have a confirmed exploitation report. The dominant weakness classes are CWE-22 (11) and CWE-59 (4). Most affected products: nltk (34), nltk/nltk (2).

CVEs per month

Last 12 months, by publish date

101112010203040506070809
Exploited share
0% vs 1% corpus
Median CVSS
7.5
Publish → KEV
—
Last 90 days
27 prev 1

Products

  • nltk 34
  • nltk/nltk 2
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36
Total CVEs
2
Critical
0
CISA KEV
0
Exploited

Worst active — by depth score

nltk vulnerabilities

CVEs affecting nltk, newest first. Open any entry for full detail, references, and exploit status.

36 CVEsRSS

CVE-2026-12259Medium· 5.3
2w ago

NLTK: Missing Post-Download Integrity Verification Allows Malicious Package Injection

NLTK: Missing Post-Download Integrity Verification Allows Malicious Package Injection

▾ Sunlitnltk · nltkEPSS 0.10%via OSV
CVE-2026-80206High
2w ago

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

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

▾ Twilightnltk · nltkEPSS 0.26%via OSV
CVE-2026-78681High
2w ago

NLTK: Entity-expansion DoS (billion laughs) via remaining raw ElementTree parses

NLTK: Entity-expansion DoS (billion laughs) via remaining raw ElementTree parses

▾ Twilightnltk · nltkEPSS 0.29%via OSV
CVE-2026-79676High
2w ago

NLTK: Corpus readers follow symlinks outside trusted roots despite pathsec enforcement

NLTK: Corpus readers follow symlinks outside trusted roots despite pathsec enforcement

▾ Twilightnltk · nltkEPSS 0.31%via OSV
CVE-2026-79657Critical
2w ago

NLTK: Allowlisted pickle loaders still permit code execution in current source

NLTK: Allowlisted pickle loaders still permit code execution in current source

▾ Midnightnltk · nltkEPSS 1.2%via OSV
CVE-2026-78683Critical
2w ago

NLTK: Unsafe Pickle Deserialization in TransitionParser Allows Remote Code Execution

NLTK: Unsafe Pickle Deserialization in TransitionParser Allows Remote Code Execution

▾ Midnightnltk · nltkEPSS 0.29%via OSV
CVE-2026-12876Medium
2w ago

NLTK: Uncontrolled resource consumption in RecursiveDescentParser via ambiguous or left-recursive grammars

NLTK: Uncontrolled resource consumption in RecursiveDescentParser via ambiguous or left-recursive grammars

▾ Sunlitnltk · nltkvia OSV
CVE-2026-81723Low· 3.7
2w ago

NLTK: Quadratic CPU Exhaustion in `XMLCorpusView._read_xml_fragment()`

NLTK: Quadratic CPU Exhaustion in `XMLCorpusView._read_xml_fragment()`

▾ Sunlitnltk · nltkEPSS 0.22%via OSV
CVE-2026-78680High· 7.8
3w ago

NLTK: Uncontrolled search path when invoking the Graphviz 'dot' binary

NLTK: Uncontrolled search path when invoking the Graphviz 'dot' binary

▾ Twilightnltk · nltkEPSS 0.12%via OSV
GHSA-2rrw-hpqm-36pvHigh· 7.5
3w ago

Duplicate Advisory: ReDoS in nltk.text.Text.findall() via unvalidated user-supplied regular expressions

Duplicate Advisory: ReDoS in nltk.text.Text.findall() via unvalidated user-supplied regular expressions

▾ Twilightnltk · nltkvia GHSA
GHSA-qp76-pq9f-gr9mHigh· 5.9
1mo ago

Duplicate Advisory: Stable FrameNet and NKJP readers parse outside-root XML in 3.9.4

Duplicate Advisory: Stable FrameNet and NKJP readers parse outside-root XML in 3.9.4

▾ Twilightnltk · nltkvia GHSA
CVE-2026-70626Medium· 6.2
1mo ago

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

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 no…

▾ Sunlitnltk · nltkEPSS 0.21%via NVD
CVE-2026-66393High· 7.5
1mo ago

NLTK versions before 3.9.4 contain an unbounded recursion vulnerability in JSONTaggedDecoder.decode_obj() that allows attackers to cause denial of service by supplying deeply nested JSON structures

NLTK versions before 3.9.4 contain an unbounded recursion vulnerability in JSONTaggedDecoder.decode_obj() that allows attackers to cause denial of service by supplying deeply nested JSON structures. Attackers can craft JSON payloads exce…

▾ Twilightnltk · nltkEPSS 0.36%via NVD
CVE-2026-65915Medium· 6.5
1mo ago

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

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…

▾ Sunlitnltk · nltkEPSS 0.36%via NVD
CVE-2026-63312High· 7.5
1mo ago

NLTK before 3.10.0 contains an arbitrary local file read vulnerability in StreamBackedCorpusView that bypasses pathsec.ENFORCE by calling builtins.open() directly instead of pathsec.open()

NLTK before 3.10.0 contains an arbitrary local file read vulnerability in StreamBackedCorpusView that bypasses pathsec.ENFORCE by calling builtins.open() directly instead of pathsec.open(). Attackers who control the fileid argument can r…

▾ Twilightnltk · nltkEPSS 0.56%via NVD
CVE-2026-62385Medium· 5.9
1mo ago

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

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. Attac…

▾ Sunlitnltk · nltkEPSS 0.37%via NVD
CVE-2026-62384High· 7.5
1mo ago

NLTK versions before 3.10.2 contain a symlink-based sandbox bypass in FramenetCorpusReader that allows attackers to read arbitrary XML files outside the corpus root

NLTK versions before 3.10.2 contain a symlink-based sandbox bypass in FramenetCorpusReader that allows attackers to read arbitrary XML files outside the corpus root. Attackers can place symlinks with names containing no path separators i…

▾ Twilightnltk · nltkEPSS 0.56%via NVD
CVE-2026-62383Medium· 5.5
1mo ago

nltk versions before 3.10.2 contain a symlink-based arbitrary file read vulnerability in IPIPANCorpusReader methods that bypass nltk.pathsec validation entirely

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 arbitra…

▾ Sunlitnltk · nltkEPSS 0.18%via NVD
CVE-2026-71514Low· 2.5
1mo ago

NLTK 3.9.4 through 3.10.2 contains a path traversal vulnerability in CrubadanCorpusReader

NLTK 3.9.4 through 3.10.2 contains a path traversal vulnerability in CrubadanCorpusReader. _load_lang_ngrams joins the corpus root with crubadan_code, the column-0 value read from the corpus table.txt mapping file, and opens the result w…

▾ Sunlitnltk · nltkEPSS 0.16%via NVD
CVE-2026-71513High· 8.8
1mo ago

NLTK before 3.10.3 contains a remote code execution vulnerability in AllowlistUnpickler that validates only the pickle module string and not the global name, allowing attackers to resolve dotted names by attribute traversal to callables …

NLTK before 3.10.3 contains a remote code execution vulnerability in AllowlistUnpickler that validates only the pickle module string and not the global name, allowing attackers to resolve dotted names by attribute traversal to callables …

▾ Twilightnltk · nltkEPSS 0.79%via NVD
CVE-2026-72818High· 7.5
1mo ago

NLTK TweetTokenizer vulnerable to denial of service through catastrophic regex backtracking

NLTK TweetTokenizer vulnerable to denial of service through catastrophic regex backtracking

▾ Twilightnltk · nltkEPSS 0.51%via OSV
CVE-2026-12372Low· 3.7
1mo ago

A Server-Side Request Forgery (SSRF) vulnerability exists in nltk/nltk versions 3.9.4 and the current develop branch

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, f…

▾ Sunlitnltk · nltkEPSS 0.26%via NVD
CVE-2026-12261Medium· 6.5PoC
1mo ago

A vulnerability in `nltk.downloader` in nltk/nltk versions <= 3.9.4 allows for cross-package resource and model poisoning

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 packa…

▾ Twilightnltk · nltkEPSS 0.21%via NVD
CVE-2026-12074High· 7.5
1mo ago

Natural Language Toolkit (NLTK) has path traversal in FramenetCorpusReader.frame() that allows arbitrary XML file read, bypassing the nlt…

Natural Language Toolkit (NLTK) has path traversal in FramenetCorpusReader.frame() that allows arbitrary XML file read, bypassing the nltk.pathsec sandbox (ENFORCE=True)

▾ Twilightnltk · nltkvia OSV
CVE-2026-12072High· 7.5
1mo ago

Natural Language Toolkit (NLTK): Path Traversal in NKJPCorpusReader leads to Arbitrary File Read and bypasses the nltk.pathsec sandbox (E…

Natural Language Toolkit (NLTK): Path Traversal in NKJPCorpusReader leads to Arbitrary File Read and bypasses the nltk.pathsec sandbox (ENFORCE=True)

▾ Twilightnltk · nltkvia OSV
CVE-2026-12061High· 7.5
1mo ago

Natural Language Toolkit (NLTK): ReDoS in NLTK ReviewsCorpusReader FEATURES regex

Natural Language Toolkit (NLTK): ReDoS in NLTK ReviewsCorpusReader FEATURES regex

▾ Twilightnltk · nltkvia OSV
CVE-2026-12075High· 8.6
1mo ago

Natural Language Toolkit (NLTK): DNS-rebinding SSRF filter bypass in nltk.pathsec.urlopen (nltk.download / nltk.data.load) defeats ENFORC…

Natural Language Toolkit (NLTK): DNS-rebinding SSRF filter bypass in nltk.pathsec.urlopen (nltk.download / nltk.data.load) defeats ENFORCE mode

▾ Twilightnltk · nltkvia OSV
CVE-2026-54293High· 7.5PoC
3mo ago

NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing

NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing. Prior to 3.10.0-rc1, nltk.data.load() in NLTK is vulnerable to path tr…

▾ Midnightnltk · nltkEPSS 0.63%via NVD
CVE-2026-33236High· 8.1
6mo ago

NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing

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, the NLTK downloader does not validate the…

▾ Twilightnltk · nltkEPSS 0.57%via NVD
CVE-2026-33231High· 7.5PoC
6mo ago

NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing

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` allows unauthentic…

▾ Midnightnltk · nltkEPSS 1.2%via NVD
nltk vulnerabilities (CVEs) · VulnSea