CVE-2026-33236: NLTK has a Downloader Path Traversal Vulnerability (AFO) - Arbitrary File Overwrite
Affects nltkSource GCVE Database
Not known to be exploited · CVSS 8.1 High : upgrade to 3.9.4 soon.
Data as of 4 Nov 2026, 04:28 UTC
- Patch
- Available – fixed in 3.9.4
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 3 Nov 2026.
What to do
Upgrade nltk to 3.9.4.
Patches and advisories
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| PyPInltk | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available in NLTK version 3.9.4 that fixes this vulnerability. Users should upgrade to version 3.9.4 or later to remediate the issue. Until patched, avoid using untrusted or malicious XML index servers with the NLTK downloader.
Description
NLTK's downloader component suffers from a path traversal vulnerability due to improper validation of XML index attributes. This flaw allows an attacker controlling a remote XML index server to specify malicious paths with traversal sequences, leading to arbitrary directory creation and file overwrite on the victim's file system, including critical system files. The vulnerability affects NLTK versions prior to 3.9.4. A patch is available in version 3.9.4.
References
- github.com/nltk/nltk/security/advisories/GHSA-469j-vmhf-r6v7 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-33236 (opens in a new tab)
- github.com/nltk/nltk/commit/89fe2ec2c6bae6e2e7a46dad65cc34231976ed8a (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:10184 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19712 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:37275 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:42644 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-33236 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2449824 (opens in a new tab)
- github.com/nltk/nltk (opens in a new tab)
- github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2026-2237.yaml (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33236.json (opens in a new tab)