CVE-2026-80205: high-severity vulnerability in nltk
NLTK before 3.10.0 ReDoS via Text.findall() unvalidated regex
Published · Updated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.7epss 0.7%
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.
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
Affected products
nltk · nltkRelated CVEs — nltk
In the same product, most dangerous first.
CVE-2021-43854HIGHInefficient Regular Expression Complexity in nltkEPSS 2.8%CVE-2026-79657CRITICALNLTK before 3.10.3 Remote Code Execution via Unsafe Pickle DeserializationEPSS 1.3%CVE-2026-33231HIGHNLTK has unauthenticated remote shutdown in nltk.app.wordnet_appEPSS 1.2%CVE-2026-71513HIGHNLTK 3.10.0 through 3.10.2 Remote Code Execution via AllowlistUnpickler Dotted-Name BypassEPSS 1.1%CVE-2026-79675CRITICALNLTK before 3.10.3 JVM Argument Injection via Per-Call OptionsEPSS 0.8%CVE-2026-72818HIGHNLTK TweetTokenizer URL Pattern Backtracks Catastrophically on Naked-Domain-Like InputEPSS 0.7%