CVE-2019-14751

Severity: high (CVSS 7.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 5.7% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2019-08-22 · updated 2026-06-17
Weakness: CWE-22

Description

NLTK Downloader before 3.4.5 is vulnerable to a directory traversal, allowing attackers to write arbitrary files via a ../ (dot dot slash) in an NLTK package (ZIP archive) that is mishandled during extraction.

Affected products

nltk: before 3.4.5 — fixed in 3.4.5

How to fix

Upgrade to a fixed version: nltk 3.4.5. Check the vendor advisory for mitigations.

References

http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00054.html
http://lists.opensuse.org/opensuse-security-announce/2020-04/msg00001.html
https://github.com/mssalvatore/CVE-2019-14751_PoC
https://github.com/nltk/nltk/blob/3.4.5/ChangeLog
https://github.com/nltk/nltk/commit/f59d7ed8df2e0e957f7f247fe218032abdbe9a10
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QI4IJGLZQ5S7C5LNRNROHAO2P526XE3D/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZGZSSEJH7RHH3RBUEVWWYT75QU67J7SE/
https://salvatoresecurity.com/zip-slip-in-nltk-cve-2019-14751/
http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00054.html
http://lists.opensuse.org/opensuse-security-announce/2020-04/msg00001.html
https://github.com/mssalvatore/CVE-2019-14751_PoC
https://github.com/nltk/nltk/blob/3.4.5/ChangeLog

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