CVE-2026-80206 Affecting nltk package, versions *


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.44% (36th percentile)

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  • Snyk IDSNYK-ECHOLATEST-NLTK-19339098
  • published27 Aug 2026
  • disclosed26 Aug 2026

Introduced: 26 Aug 2026

CVE-2026-80206  (opens in a new tab)

How to fix?

There is no fixed version for Echo:latest nltk.

NVD Description

Note: Versions mentioned in the description apply only to the upstream nltk package and not the nltk package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

NLTK before 3.10.3 contains a regular expression denial of service (ReDoS) vulnerability in the tgrep module. The _tgrep_node_action function compiles user-supplied regular expressions embedded in /regex/ pattern nodes and executes them via re.search against tree node labels without any validation or timeout. An attacker who controls the tgrep pattern (e.g., via tgrep_positions() or tgrep_compile() exposed to external input) can supply a pattern that triggers catastrophic backtracking, causing indefinite CPU saturation that blocks the Python process.