High severity · published Oct 13, 2026
CVE-2026-109956
NLTK through 3.10.3 Path Traversal via WekaClassifier Model Path
7.0
CVSS
0.3%
EPSS
No
On KEV
Description
NLTK through 3.10.3 contains a path traversal vulnerability in WekaClassifier that allows attackers to bypass nltk.pathsec containment by supplying unvalidated model paths. Attackers controlling the model_filename or model argument can make the weka JVM write files via -d or probe files via -l outside allowed data roots.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:L
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
High
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 25% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
NL
nltk · nltk
through 3.10.3 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-109956
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-109956
vendor-advisory
https://github.com/nltk/nltk/security/advisories/GHSA-j456-xh4h-cpf2
third-party-advisory
https://www.vulncheck.com/advisories/nltk-through-3.10.3-path-traversal-via-wekaclassifier-model-path
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