CVE-2026-81724
NLTK before 3.10.3 Denial of Service via Uncontrolled Recursion
CVSS Score
5.3
EPSS Score
0.0%
EPSS Percentile
0th
NLTK before 3.10.3 contains an uncontrolled recursion vulnerability in nltk.featstruct.FeatStructReader that allows unauthenticated attackers to cause a denial of service by supplying deeply nested feature-structure input. Attackers can craft trivial payloads with nested brackets that exceed Python's recursion limit and raise an unhandled RecursionError, crashing applications that parse user-supplied feature structures or feature grammars.
| CWE | CWE-674 |
| Vendor | nltk |
| Product | nltk |
| Published | Aug 27, 2026 |
| Last Updated | Aug 27, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low
Affected Versions
nltk / nltk
0 < 3.10.3
References
Credits
🔍 JoshgunAbdullayev