CVE-2026-63311

medium Red Hat
CVSS v3 Base Score
4.2
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N
EPSS Score
0.2%
Exploitation probability in 30 days
Top 85% most likely to be exploited
Attack Characteristics
Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Published: August 22, 2026 (15 days ago)
Last Modified: August 22, 2026
Vendor: Red Hat
Source: REDHAT

Description

NLTK before 3.10.0 (affected versions <= 3.9.4) contains a server-side request forgery (SSRF) vulnerability in the validate_network_url() function in nltk/pathsec.py. The _resolve_hostname() helper catches OSError and ValueError during socket.getaddrinfo() and returns an empty list; when DNS resolution fails, the validation loop executes no IP checks and the function fails open, allowing urlopen() to proceed without validation. An attacker who can trigger DNS resolution failures or use DNS rebinding can bypass SSRF protections and reach restricted network resources, including cloud metadata endpoints (e.g., 169.254.169.254).

CWE

CWE-918

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 🔗 github.com 🔗 www.vulncheck.com