CVE-2026-80205
Published:August 26, 2026
Updated:September 24, 2026
NLTK versions before 3.10.0 contain a regular expression denial of service vulnerability in Text.findall() and TokenSearcher.findall() methods that accept user-supplied regular expressions without validation or timeout. Attackers can supply crafted regex patterns that cause catastrophic backtracking, resulting in indefinite CPU saturation and denial of service to all users of the Python process.
Affected Packages
nltk (CONDA):
Affected version(s) >=2.0.3 <3.10.0Fix Suggestion:
Update to version 3.10.0nltk (CONDA):
Affected version(s) >=2.0.3 <3.10.0Fix Suggestion:
Update to version 3.10.0nltk (PYTHON):
Affected version(s) >=0.8 <3.10.0Fix Suggestion:
Update to version 3.10.0Related Resources (10)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
Inefficient Regular Expression Complexity
EPSS
Base Score:
0.49