{"id":"CVE-2026-126302","kind":"vulnerability","aliases":["CVE-2026-126302"],"related":[],"title":"NLTK: symlink following lets attackers read SQLite files outside sandbox","description":"NLTK from 3.9.4 before 3.10.4 contains a symlink following vulnerability in nltk.sem.chat80.sql_query() that bypasses the pathsec data-root sandbox containment check. Attackers who can write into a trusted NLTK data root can plant a symbolic link to read SQLite databases outside the sandbox.","summary":"NLTK versions from 3.9.4 before 3.10.4 have a flaw in the chat80 sql_query() function that follows symbolic links and bypasses the data-root sandbox check. An attacker who can write into a trusted NLTK data directory can plant a symlink and read SQLite databases located outside that sandbox.","severity":"medium","cvss":4.8,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["nltk","package","python"],"not_affected_if":["chat80-unused","read-only-data-root"],"how_to_check":"- Run `pip show nltk` and check whether the version is at least `3.10.4`.\n- Check whether your application calls `nltk.sem.chat80.sql_query()` with data paths that other users or processes can write to.","fix":"- NLTK: move to `3.10.4` or later (from the NVD range 3.9.4 before 3.10.4).","status":"open","published_at":"2026-11-13T10:17:35+00:00","first_seen_at":"2026-11-13T10:47:15+00:00","triaged_at":"2026-11-13T10:58:43+00:00","updated_at":"2026-11-13T10:58:43+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-11-13T10:58:43Z","model":"claude-haiku-5-5","output":{"fix":"- NLTK: move to `3.10.4` or later (from the NVD range 3.9.4 before 3.10.4).","reach":"local","title":"NLTK: symlink following lets attackers read SQLite files outside sandbox","impact":"medium","summary":"NLTK versions from 3.9.4 before 3.10.4 have a flaw in the chat80 sql_query() function that follows symbolic links and bypasses the data-root sandbox check. An attacker who can write into a trusted NLTK data directory can plant a symlink and read SQLite databases located outside that sandbox.","audience":"developers","category":"package","nicknames":[],"who_cares":["python","nltk"],"confidence":0.7,"fix_status":"available","needs_auth":"yes","worst_case":"local file read of SQLite databases outside the sandbox","analyst_note":"","how_to_check":"- Run `pip show nltk` and check whether the version is at least `3.10.4`.\n- Check whether your application calls `nltk.sem.chat80.sql_query()` with data paths that other users or processes can write to.","plain_action":"","product_name":"","needs_analyst":false,"not_affected_if":["chat80-unused","read-only-data-root"],"who_is_affected":"Only applications that use NLTK's chat80 sql_query() function and keep NLTK data in a directory where untrusted users can write. Systems that do not call this function or do not share writable data roots are unlikely to be exposed.","user_interaction":"no","product_ecosystem":"","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.000726,"input_tokens":4619,"output_tokens":529,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-126302':13A,16A '-2026':12A,15A '3.10.4':25B,74C '3.9.4':23B,72C 'attack':5A,48B,93C 'bypass':40B,84C 'chat80':31B 'check':46B,92C 'contain':75C,91C 'cve':11A,14A 'data':43B,56B,88C,101C 'data-root':42B,87C 'databas':65B,111C 'directori':57B 'file':8A 'flaw':28B 'follow':3A,36B,78C 'function':34B 'let':4A 'link':38B,107C 'locat':66B 'nltk':1A,17B,20B,55B,70C,100C 'nltk.sem.chat80.sql':81C 'outsid':9A,67B,112C 'packag':18B 'pathsec':86C 'plant':59B,104C 'python':19B 'queri':33B,82C 'read':6A,63B,109C 'root':44B,89C,102C 'sandbox':10A,45B,69B,90C,114C 'sql':32B 'sqlite':7A,64B,110C 'symbol':37B,106C 'symlink':2A,61B,77C 'trust':54B,99C 'version':21B 'vulner':79C 'write':51B,96C","nicknames":[],"mitigations":[],"who_affected":"Only applications that use NLTK's chat80 sql_query() function and keep NLTK data in a directory where untrusted users can write. Systems that do not call this function or do not share writable data roots are unlikely to be exposed.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"developers","plain_action":null,"pkeys":[],"ptokens":[],"labels":["medium","nltk","package","python"],"campaign_type":null,"search_a":"'-126302':13A,16A '-2026':12A,15A 'attack':5A 'cve':11A,14A 'file':8A 'follow':3A 'let':4A 'nltk':1A 'outsid':9A 'read':6A 'sandbox':10A 'sqlite':7A 'symlink':2A","search_b":"'3.10.4':25B '3.9.4':23B 'attack':48B 'bypass':40B 'chat80':31B 'check':46B 'data':43B,56B 'data-root':42B 'databas':65B 'directori':57B 'flaw':28B 'follow':36B 'function':34B 'link':38B 'locat':66B 'nltk':17B,20B,55B 'outsid':67B 'packag':18B 'plant':59B 'python':19B 'queri':33B 'read':63B 'root':44B 'sandbox':45B,69B 'sql':32B 'sqlite':64B 'symbol':37B 'symlink':61B 'trust':54B 'version':21B 'write':51B","search_c":"'3.10.4':74C '3.9.4':72C 'attack':93C 'bypass':84C 'check':92C 'contain':75C,91C 'data':88C,101C 'data-root':87C 'databas':111C 'follow':78C 'link':107C 'nltk':70C,100C 'nltk.sem.chat80.sql':81C 'outsid':112C 'pathsec':86C 'plant':104C 'queri':82C 'read':109C 'root':89C,102C 'sandbox':90C,114C 'sqlite':110C 'symbol':106C 'symlink':77C 'trust':99C 'vulner':79C 'write':96C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-10-26T14:13:41+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_by":"disclosure@vulncheck.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-126302","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-126302","severity":null,"published_at":"2026-11-13T10:17:35+00:00","modified_at":"2026-11-13T10:17:35+00:00","first_seen_at":"2026-11-13T10:47:15+00:00","fetched_at":"2026-11-13T10:47:15+00:00","note":null}],"documents":[{"id":144933,"url":"https://github.com/nltk/nltk/security/advisories/GHSA-xmfg-f9cm-w86q","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-10-26T14:13:41+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":144934,"url":"https://www.vulncheck.com/advisories/nltk-3.9.4-before-3.10.4-symlink-sandbox-escape-via-chat80-sql-query","title":"Third-party advisory: www.vulncheck.com","kind":"advisory","source":"nvd","publisher":"research","text":null,"published_at":null,"relation":"advisory","confidence":null,"note":"Third-party advisory: www.vulncheck.com"}],"disclosures":[],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}