Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Nltk | Nltk | < 3.10.3 |
Related Weaknesses (CWE)
References
- https://github.com/nltk/nltk/security/advisories/GHSA-cw6x-m8jw-qmrhExploitVendor Advisory
- https://www.vulncheck.com/advisories/nltk-before-3.10.3-denial-of-service-via-unThird Party Advisory
- https://github.com/nltk/nltk/security/advisories/GHSA-cw6x-m8jw-qmrhExploitVendor Advisory
FAQ
What is CVE-2026-81724?
CVE-2026-81724 is a vulnerability with a CVSS score of 5.3 (MEDIUM). 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 fe...
How severe is CVE-2026-81724?
CVE-2026-81724 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-81724?
Check the references section above for vendor advisories and patch information. Affected products include: Nltk Nltk.