High severity · published Mar 20, 2026
CVE-2026-33236
NLTK has a Downloader Path Traversal Vulnerability (AFO) - Arbitrary File Overwrite
8.1
CVSS
0.6%
EPSS
No
On KEV
Description
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 `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, arbitrary file creation, and arbitrary file overwrite. Commit 89fe2ec2c6bae6e2e7a46dad65cc34231976ed8a patches the issue.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
None
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 48% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
NL
nltk · nltk
<= 3.9.3 · source: vendor, NVD
LC
Lightspeed Core · Red Hat
All versions, or not specified · source: CISA
OL
OpenShift Lightspeed · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Ansible Automation Platform 2 · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat OpenShift AI (RHOAI) · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat OpenShift AI 2.25 · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat OpenShift AI 3.3 · Red Hat
All versions, or not specified · source: CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33236
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-33236
Patch
https://github.com/nltk/nltk/commit/89fe2ec2c6bae6e2e7a46dad65cc34231976ed8a
Exploit
https://github.com/nltk/nltk/security/advisories/GHSA-469j-vmhf-r6v7
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:10184
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:19712
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:37275
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:42644
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