Server-Side Request Forgery (SSRF) Affecting nltk package, versions <3.10.3-1


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.25% (17th percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-NLTK-19256965
  • published25 Aug 2026
  • disclosed25 Aug 2026

Introduced: 25 Aug 2026

NewCVE-2026-78682  (opens in a new tab)
CWE-918  (opens in a new tab)

How to fix?

Upgrade Debian:unstable nltk to version 3.10.3-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream nltk package and not the nltk package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

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 Base Scores

version 3.1