{"cve":"CVE-2026-54293","nvd":{"published":"2026-06-22T19:17:20.983","modified":"2026-09-09T13:20:30.723","status":"Modified","description":"NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing. Prior to 3.10.0-rc1, nltk.data.load() in NLTK is vulnerable to path traversal via URL-encoded path separators and traversal segments when using the nltk: URL scheme. The unsafe-path regex check is performed before url2pathname() decodes the %xx sequences (a classic decode-after-check / TOCTOU-style flaw), allowing an attacker to bypass the protection documented in NLTK's SECURITY.md and read arbitrary files from the filesystem. While literal traversal strings such as ../../../etc/passwd are correctly blocked, encoded variants such as %2fetc%2fpasswd, %2e%2e%2f..., and ..%2f..%2f slip past the regex and are subsequently decoded into a real filesystem path. This vulnerability is fixed in 3.10.0-rc1.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","score":7.5},"cwes":["CWE-22"],"references":["https://github.com/nltk/nltk/pull/3575","https://github.com/nltk/nltk/security/advisories/GHSA-p4gq-832x-fm9v","https://access.redhat.com/errata/RHSA-2026:42644","https://access.redhat.com/errata/RHSA-2026:60520","https://access.redhat.com/errata/RHSA-2026:65126"],"products":["nltk:nltk"],"source":"nvd","synced_at":"2026-10-19T22:39:28.638635428+00:00"},"epss":{"cve":"CVE-2026-54293","score":0.00633,"percentile":0.50341,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-p4gq-832x-fm9v","url":"https://osv.dev/vulnerability/GHSA-p4gq-832x-fm9v","summary":"Natural Language Toolkit (NLTK): URL-Encoded Path Traversal in nltk.data.load() Allows Arbitrary Local File Read","modified":"2026-09-10T03:51:09.128527813Z","packages":[{"ecosystem":"PyPI","name":"nltk","purl":"pkg:pypi/nltk","ranges":["<3.10.0"],"fixed":["3.10.0"]}]},{"id":"PYSEC-2026-2078","url":"https://osv.dev/vulnerability/PYSEC-2026-2078","summary":"","modified":"2026-07-08T07:15:14.576470165Z","packages":[{"ecosystem":"PyPI","name":"nltk","purl":"pkg:pypi/nltk","ranges":["<3.10.0"],"fixed":["3.10.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}