CVE-2026-12261

medium Red Hat
CVSS v3 Base Score
5.3
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
EPSS Score
0.2%
Exploitation probability in 30 days
Top 91% most likely to be exploited
Attack Characteristics
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Confidentiality
None
Integrity
High
Availability
None
Published: August 7, 2026 (30 days ago)
Last Modified: August 7, 2026
Vendor: Red Hat
Source: REDHAT

Description

A vulnerability in `nltk.downloader` in nltk/nltk versions <= 3.9.4 allows for cross-package resource and model poisoning. The downloader extracts package archives into shared namespaces such as `corpora/` and `taggers/` instead of package-isolated roots, and validates package integrity only after the archive has been written and extracted. This design flaw enables one package to overwrite another package's trusted resources within the same namespace, making the changes immediately active through ordinary NLTK APIs. This issue persists across fresh interpreter restarts and can affect downstream workflows, including machine learning pipelines and reproducibility-sensitive environments.

CWE

CWE-367

Affected Products

Exploit IntelligenceLightspeed CoreOpenShift LightspeedRed Hat Ansible Automation Platform 2Red Hat OpenShift AI (RHOAI)

References

🔗 bugzilla.redhat.com 🔗 www.cve.org 🔗 nvd.nist.gov 🔗 huntr.com