CVE-2026-109956: nltk · Path Traversal
Affects nltkSource CVE Database V5
Public exploit available · CVSS 8.3 High.
Data as of 26 Oct 2026, 20:12 UTC
- CISA SSVC
- Exploitation
- Proof of concept is public or traded
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-10-26.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:L/SC:N/SI:N/SA:NExploitation evidence
t = 0 is the CVE’s publication on cve.org
Disclosed: evidence found.
CVE published 13 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
CISA SSVC: proof of concept public
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
Timeline
CVE ID reserved
by VulnCheck
, 2 hours before disclosure
CVE published
on cve.org
, t = 0
CISA SSVC assessment
proof of concept public
, 13 days after disclosure
In Threat Radar
record ingested
, 13 days after disclosure
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA SSVC, the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| nltknltk | Affected
| Fixed in– |
PyPInltkpkg:pypi/nltkOther threats | 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
Since the vulnerability is in versions up to 3.10.3, users should upgrade to a version later than 3.10.3 if available. If no fixed version exists yet, users should avoid passing untrusted input to the model_filename or model arguments in WekaClassifier to prevent exploitation. Monitor the vendor advisory for updates and apply official patches once released.
Description
NLTK versions up to 3.10.3 have a path traversal vulnerability in the WekaClassifier component. This flaw allows attackers who control the model filename or model argument to bypass path containment checks and cause the Weka JVM to write or probe files outside of permitted directories.