CVE-2026-63310

Published Aug 22, 2026

Last updated 2 days ago

CVSS critical 9.3

Overview

Description: 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.
Source: disclosure@vulncheck.com
NVD status: Received

Risk scores

CVSS 4.0

Type: Secondary
Base score: 9.3
Impact score: -
Exploitability score: -
Vector string: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Severity: CRITICAL

CVSS 3.1

Type: Primary
Base score: 7.1
Impact score: 5.5
Exploitability score: 1.6
Vector string: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:H
Severity: HIGH

Weaknesses

disclosure@vulncheck.com: CWE-494

Hype score: Not currently trending

References

Sources include official advisories and independent security research.