Nltk Nltk
CVE-2026-65915
NLTK versions before 3.10.0 contain a logic bug in FileSystemPathPointer.open() where the sandbox validation check compares a normalized path against itself, making the security check permanently inert. Attackers can pass file:// URLs to nltk.data.load() to read arbitrary files accessible to the process user, including credentials and configuration files.
What this means for your business
- It affects Nltk. It matters if your company, or a supplier that handles your data, runs it.
- Code showing how to exploit it has been published, but real attacks have not been confirmed.
- An attacker can use it remotely, over a network, with an ordinary user login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 0.4% chance of attack attempts being seen in the next 30 days, ranking above 29% of all known flaws.
What to do
- 1Check whether your company or your suppliers run Nltk, and which version. The affected versions are listed further down this page.
- 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.
Fastnexa security experts
Not sure if your company is exposed to CVE-2026-65915?
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Scoring
- CVSS
- 6.5 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N- CVSS v4
- 7.1
- Weakness
- CWE-284
- Assigned by
- disclosure@vulncheck.com
Dates
- Published
- 2026-08-22
- Last modified
- 2026-08-31
- Sources
- NVD
Affected products
- Nltk Nltk- 3.10.0
As listed in the NVD configuration data. Not a statement about your estate.