Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
The nltk package, versions before 3.9, is vulnerable to unsafe deserialization. If untrusted data packages containing pickled Python code are downloaded through NLTK's built-in data download functionality, an attacker can achieve remote code execution. The source names averaged_perceptron_tagger and punkt as examples affected by this. Upgrade nltk to version 3.9 or later.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 7.5 | High | 3.1 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H | GitHub Advisory Database |
- CISA KEV Not listed.
- EPSS 0.013, the 71st percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:35 UTC First seen by agentprime
- 31 Oct 2026, 14:35 UTC Confirmed by OSV
Sources
- GitHub Advisory Database: GHSA-cgvx-9447-vcch
- OSV: GHSA-cgvx-9447-vcch
- nvd.nist.gov/vuln/detail/CVE-2024-39705
- github.com/nltk/nltk/issues/2522
- github.com/nltk/nltk/issues/3266
- github.com/nltk/nltk/commit/441aecb7d33014bd08672232c6c8bb69c2ceaba2
- github.com/nltk/nltk
- github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2024-167.yaml
- www.vicarius.io/vsociety/posts/rce-in-python-nltk-cve-2024-39705-39706