CVE-2026-80205 PUBLISHED

NLTK before 3.10.0 ReDoS via Text.findall() unvalidated regex

Assigner: VulnCheck
Reserved: 25.08.2026 Published: 26.08.2026 Updated: 26.08.2026

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.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS Score: 8.7

Product Status

Vendor nltk
Product nltk
Versions Default: unaffected
  • affected from 0 to 3.10.0 (excl.)
  • Version 3.10.0 is unaffected

Credits

  • infycore reporter
  • ekaf analyst
  • agent-kira finder

References

Problem Types

  • Inefficient Regular Expression Complexity CWE