Vulnerability Description
NLTK before 3.10.3 contains a server-side request forgery vulnerability in nltk.pathsec.urlopen (and callers nltk.data.load, nltk.downloader.Downloader.index/download) when an HTTP proxy is configured. pathsec.urlopen validates the requested hostname locally, but proxy-handler inheritance disables the safe HTTP/HTTPS handlers so the actual fetch is performed by the proxy against a destination that is never re-validated. An attacker can supply a validated public URL that the proxy forwards to an internal loopback-only service, allowing disclosure of internal HTTP resources, loading of forged downloader indexes, and installation of attacker-chosen package content.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Nltk | Nltk | < 3.10.3 |
Related Weaknesses (CWE)
References
- https://github.com/nltk/nltk/security/advisories/GHSA-6ww7-3frv-cqxhExploitVendor Advisory
- https://www.vulncheck.com/advisories/nltk-before-ssrf-protection-bypass-via-proxThird Party Advisory
- https://github.com/nltk/nltk/security/advisories/GHSA-6ww7-3frv-cqxhExploitVendor Advisory
FAQ
What is CVE-2026-78682?
CVE-2026-78682 is a vulnerability with a CVSS score of 7.5 (HIGH). NLTK before 3.10.3 contains a server-side request forgery vulnerability in nltk.pathsec.urlopen (and callers nltk.data.load, nltk.downloader.Downloader.index/download) when an HTTP proxy is configured...
How severe is CVE-2026-78682?
CVE-2026-78682 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-78682?
Check the references section above for vendor advisories and patch information. Affected products include: Nltk Nltk.