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.
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History
Thu, 27 Aug 2026 16:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | NLTK before 3.10.3 Denial of Service via Uncontrolled Recursion | |
| First Time appeared |
Nltk
Nltk nltk |
|
| Weaknesses | CWE-674 | |
| CPEs | cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Nltk
Nltk nltk |
|
| References |
| |
| Metrics |
cvssV3_1
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MITRE
Status: PUBLISHED
Assigner: VulnCheck
Published:
Updated: 2026-08-27T14:51:17.358Z
Reserved: 2026-08-27T11:15:29.420Z
Link: CVE-2026-81724
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Weaknesses