Server-Side Request Forgery (SSRF) in Natural Language Toolkit - CVE-2026-54296
Published: August 7, 2026
Vulnerability identifier: #VU141242
CSH Severity: High
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:L/SI:N/SA:N]
CVE-ID: CVE-2026-54296
CWE-ID: CWE-918
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to server-side request forgery in nltk.pathsec.urlopen when validating a hostname before urllib performs a separate connection-time DNS resolution. A remote attacker can supply a hostname with attacker-controlled DNS rebinding records to disclose sensitive information.
The issue defeats the documented ENFORCE mode and can expose responses from internal-only HTTP services, including loopback administrative interfaces and cloud metadata endpoints.
Affected software
Natural Language Toolkit
How to mitigate CVE-2026-54296
Install security update from vendor's website.
Natural Language Toolkit - update to 3.10.0