CVE-2026-80205NLTK before 3.10.0 ReDoS via Text.findall() unvalidated regex

Description

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.

Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.

Affected products and versions

References and patches

• GitHub Security Advisory (GHSA-rrv8-h7p8-rx55) vendor-advisoryExploitVendor Advisory
• VulnCheck Advisory: NLTK before 3.10.0 ReDoS via Text.findall() unvalidated regex third-party-advisoryThird Party Advisory
• http://www.openwall.com/lists/oss-security/2026/09/01/3