CVE-2026-81727
NLTK before 3.10.3 Hardlink File Overwrite via downloader
CVSS Score
7.1
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-59 |
| Vendor | nltk |
| Product | nltk |
| Published | Aug 27, 2026 |
| Last Updated | Aug 27, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
High
Affected Versions
nltk / nltk
0 < 3.10.3