Upstream information

CVE-2026-12259 at MITRE

Description

In nltk version 3.9.4, the `nltk.downloader.Downloader._download_package()` function writes downloaded package bytes to disk and may extract them before enforcing SHA-256 or MD5 checksum validation. This allows an attacker to tamper with the package response body for `info.url` through a compromised mirror, malicious proxy, or other source-substitution condition, leading to the installation of attacker-controlled package bytes. The vulnerability can result in malicious corpus or model content being trusted by downstream users or applications.

SUSE information

Overall state of this security issue: Does not affect SUSE products

This issue is currently rated as having moderate severity.

CVSS v3 Scores
CVSS detail CNA (Huntr.dev)
Base Score 5.3
Vector CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
Attack Vector Network
Attack Complexity High
Privileges Required None
User Interaction Required
Scope Unchanged
Confidentiality Impact None
Integrity Impact High
Availability Impact None
CVSSv3 Version 3
SUSE Bugzilla entry: 1273913 [NEW]

No SUSE Security Announcements cross referenced.

SUSE Timeline for this CVE

CVE page created: Wed Aug 5 21:26:46 2026
CVE page last modified: Wed Aug 5 21:26:46 2026