{"id":"CVE-2026-54293","summary":"NLTK: URL-Encoded Path Traversal in nltk.data.load() Allows Arbitrary Local File Read","details":"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.","aliases":["GHSA-p4gq-832x-fm9v","PYSEC-2026-2078"],"modified":"2026-07-08T15:29:23.058365523Z","published":"2026-06-22T17:25:05.611Z","related":["CGA-mg56-c29x-gf4f","openSUSE-SU-2026:11098-1"],"database_specific":{"cwe_ids":["CWE-22"],"cna_assigner":"GitHub_M","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54293.json"},"references":[{"type":"WEB","url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-54293.json"},{"type":"ADVISORY","url":"https://access.redhat.com/security/cve/CVE-2026-54293"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54293.json"},{"type":"ADVISORY","url":"https://github.com/nltk/nltk/security/advisories/GHSA-p4gq-832x-fm9v"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54293"},{"type":"REPORT","url":"https://bugzilla.redhat.com/show_bug.cgi?id=2491486"},{"type":"FIX","url":"https://github.com/nltk/nltk/pull/3575"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/nltk/nltk","events":[{"introduced":"0"},{"fixed":"16a32d680d070254d5744e33fa83f9c0056d5a1f"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"3.10.0-rc1"}],"source":"AFFECTED_FIELD"}}],"versions":["3.9.4","3.9.3","v3.9.2","3.9.2","3.9.1","3.9","3.8.2","3.8.1","3.8","3.7","3.6.7","3.6.6","3.6.5","3.6.2","3.6.1","3.6","3.5","3.5b1","3.4.4","3.4.3","3.4.1","3.4","3.3","3.2.5","3.2.4","3.2.3","3.2.2","3.2.1","3.2","3.1","3.0.5","3.0.4","3.0.3","3.0.2","3.0.0b1","3.0a4","2.0.1rc4","2.0.1rc3","2.0.1rc2","2.0.1rc1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-54293.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"}]}