Not a U.S. government website. NDD is an independent vulnerability database by Volerion and is not affiliated with or endorsed by NIST or NVD.
VOLERION
Volerion Security Research

NOT DEFERRED DATABASE

VULNERABILITIES

CVE-2026-81725 Details

Description

NLTK before 3.10.3 contains a regular expression denial of service vulnerability in Pl196xCorpusReader that allows attackers to cause quadratic CPU consumption by supplying malformed TEI blocks with many unmatched opening tags. Attackers can exploit lazy regex patterns in the read_block method through public APIs like words() and tagged_words() to force repeated rescans and achieve near-quadratic runtime growth.

Metrics

CVSS 3.x Severity and Vector Strings:

CNA: [email protected]CVSS-B:3.7 LOWVector:CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

References to Advisories, Solutions, and Tools

By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.

URLSource(s)Tag(s)
https://github.com/nltk/nltk/security/advisories/GHSA-8mpw-7fpc-4gqj [email protected]ExploitVendor Advisory
https://www.vulncheck.com/advisories/nltk-before-3.10.3-regular-expression-denial-of-service-via-pl196xcorpusreader [email protected]Third Party Advisory

Weakness Enumeration

CWE-IDCWE NameSource
CWE-400Uncontrolled Resource Consumption[email protected]

Affected Products

ProductVersions
nltk nltk
< 3.10.3

CPE

  • cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:*

Remediation

  • No remediation found in references.

Change History

3 change records found show changes

QUICK INFO

CVE Dictionary Entry:
CVE-2026-81725
NVD Published Date:
Aug 27, 2026
NVD Last Modified:
Sep 1, 2026
Source:
[email protected]
CVE-2026-81725 Details - Not Deferred