GHSA-crp9-r7rq-c8cg
Duplicate Advisory: pathsec SSRF protection can be bypassed when a proxy is configured
Summary
## Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-6ww7-3frv-cqxh. This link is maintained to preserve external references. ## Original 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.
Affected packages
| Ecosystem | Package | Affected versions | Fixed versions |
|---|---|---|---|
| PyPI | nltk | — | — |
Remediation: No patched version is listed by GitHub.
References
Includes data from the GitHub Advisory Database, licensed under CC-BY 4.0.