This page tracks the Ubuntu fix status. The vulnerability itself is described on the main CVE page. View CVE-2026-81727 →

UBUNTU-CVE-2026-81727

NLTK versions before 3.10.3 contain a filesystem containment bypass vulnerability in the Downloader.download and Downloader.incr_download methods that...

Original description

The description as published by the source.

NLTK versions before 3.10.3 contain a filesystem containment bypass vulnerability in the Downloader.download and Downloader.incr_download methods that allows attackers to overwrite files outside the install root through pre-existing hardlinks. Attackers with write access to a shared downloader directory can create hardlinks pointing to outside-root files that are then overwritten during normal package extraction, mutating files outside the intended install tree.

Source: OSV.dev (Open Source Vulnerabilities) OSV