UNKNOWNPyPI →
NLTK versions before 3.9.4 contain an unbounded recursion vulnerability in JSONTaggedDecoder.decode_obj() that allows at
NLTK versions before 3.9.4 contain an unbounded recursion vulnerability in JSONTaggedDecoder.decode_obj() that allows attackers to cause denial of service by supplying deeply nested JSON structures. Attackers can craft JSON payloads exceeding the recursion limit to trigger an unhandled RecursionError that crashes the Python process.
Affected packages
- nltk— before 3.9.4
Exploit signal
- Known exploited (CISA KEV)
- No
- EPSS score
- —
- EPSS percentile
- —
EPSS is the probability a CVE is exploited in the wild; percentile is its rank among all CVEs.
Sources
- https://www.vulncheck.com/advisories/nltk-before-denial-of-service-via-jsontaggeddecoder
- https://github.com/nltk/nltk/security/advisories/GHSA-rf74-v2fm-23pw
Structured record: https://osv.dev/vulnerability/PYSEC-2026-3724
Recommended response stack
Snyk — Scan your dependencies in CI and fix this vulnerability.→Socket — Detect malicious and compromised packages before they ship.→
Some links are affiliate links — HackTribune may earn a commission at no extra cost to you.
Get incidents like this as alerts for your stack.
Join the beta