CVE-2026-63310
NLTK before 3.9.3 Missing Post-Download Integrity Verification
CVSS Score
7.1
EPSS Score
0.0%
EPSS Percentile
0th
NLTK before 3.9.3 fails to verify file integrity after downloading packages and before extraction in the downloader module. Attackers can perform man-in-the-middle attacks or DNS poisoning to inject malicious package contents that are extracted without validation.
| CWE | CWE-494 |
| Vendor | nltk |
| Product | nltk |
| Published | Aug 22, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:H Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
High
Availability
High
Affected Versions
nltk / nltk
0 < 3.9.3