CVE-2026-63310

CRITICAL CVSS 4.0: 9.3 EPSS 0.12%
Updated Aug 31, 2026
Nltk
Parameter Value
CVSS 9.3 (CRITICAL)
Affected Versions before 3.9.3
Fixed In 3.9.3
Type CWE-494
Vendor Nltk
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service

CVSS Vector v4.0

Weakness Type (CWE)

Vulnerable Products 1

Configuration From (including) Up to (excluding)
Nltk Nltk
cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:*
3.9.3