CVE-2026-81723
Published:August 27, 2026
Updated:September 24, 2026
NLTK versions before 3.10.3 contain a quadratic CPU exhaustion vulnerability in XMLCorpusView._read_xml_fragment() that rescans accumulated XML fragments on every 1 KiB block read. Attackers can provide malformed XML corpus files to cause severe CPU consumption and denial of service through affected readers like BNCCorpusReader.
Affected Packages
nltk (CONDA):
Affected version(s) >=2.0.3 <3.10.3Fix Suggestion:
Update to version 3.10.3https://github.com/nltk/nltk.git (GITHUB):
Affected version(s) >=v3.9.2 <v3.10.3Fix Suggestion:
Update to version v3.10.3nltk (PYTHON):
Affected version(s) >=0.8 <3.10.3Fix Suggestion:
Update to version 3.10.3nltk (PYTHON):
Affected version(s) >=0.8 <3.10.3Fix Suggestion:
Update to version 3.10.3Related Resources (7)
Do you need more information?
Contact UsCVSS v4
Base Score:
6.3
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
PRESENT
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
LOW
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
3.7
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Weakness Type (CWE)
EPSS
Base Score:
0.22