This page tracks the Ubuntu fix status. The vulnerability itself is described on the main CVE page. View CVE-2026-63311 →
Categories
UBUNTU-CVE-2026-63311

NLTK before 3.10.0 (affected versions

Original description

The description as published by the source.

NLTK before 3.10.0 (affected versions <= 3.9.4) contains a server-side request forgery (SSRF) vulnerability in the validate_network_url() function in nltk/pathsec.py. The _resolve_hostname() helper catches OSError and ValueError during socket.getaddrinfo() and returns an empty list; when DNS resolution fails, the validation loop executes no IP checks and the function fails open, allowing urlopen() to proceed without validation. An attacker who can trigger DNS resolution failures or use DNS rebinding can bypass SSRF protections and reach restricted network resources, including cloud metadata endpoints (e.g., 169.254.169.254).

Source: OSV.dev (Open Source Vulnerabilities) OSV

Affected packages

Ubuntu:Pro:14.04:LTS nltk
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:Pro:16.04:LTS nltk
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:Pro:18.04:LTS nltk
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:Pro:20.04:LTS nltk
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:Pro:22.04:LTS nltk
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:Pro:24.04:LTS nltk
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:26.10 nltk
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:Pro:26.04:LTS nltk
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]

References

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