{"id":"CVE-2026-123534","kind":"vulnerability","aliases":["CVE-2026-123534"],"related":[],"title":"Tornado: path traversal in static_url() hashes files outside static path","description":"Tornado before 6.6 contains a path traversal vulnerability in RequestHandler.static_url() and get_version() that allows attackers to hash files outside static_path using ../ sequences. Attackers controlling input passed to static_url() can obtain SHA-512 hashes of readable files to confirm their existence, or reference /dev/zero to block the event loop indefinitely.","summary":"Tornado's RequestHandler.static_url() and get_version() accept ../ sequences, so they hash files outside the static_path directory. An attacker who controls the input can learn whether readable files exist via SHA-512 hashes, or block the event loop by pointing it at /dev/zero.","severity":"high","cvss":8.3,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["package","python","tornado","web-apps"],"not_affected_if":["hard-coded-static-paths","tornado-6.6-or-later"],"how_to_check":"- Check the installed Tornado version with `python -c \"import tornado; print(tornado.version)\"`\n- Look for application code that passes user-controlled input into `static_url()`","fix":"- Tornado: move to `6.6` or later","status":"open","published_at":"2026-11-08T02:16:43+00:00","first_seen_at":"2026-11-08T02:21:10+00:00","triaged_at":"2026-11-08T02:23:14+00:00","updated_at":"2026-11-08T02:23:14+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-11-08T02:23:14Z","model":"claude-haiku-5-5","output":{"fix":"- Tornado: move to `6.6` or later","reach":"internet","title":"Tornado: path traversal in static_url() hashes files outside static path","impact":"low","summary":"Tornado's RequestHandler.static_url() and get_version() accept ../ sequences, so they hash files outside the static_path directory. An attacker who controls the input can learn whether readable files exist via SHA-512 hashes, or block the event loop by pointing it at /dev/zero.","audience":"developers","category":"package","nicknames":[],"who_cares":["python","tornado","web-apps"],"confidence":0.7,"fix_status":"available","needs_auth":"unknown","worst_case":"attacker learns file existence and can stall the event loop","analyst_note":"","how_to_check":"- Check the installed Tornado version with `python -c \"import tornado; print(tornado.version)\"`\n- Look for application code that passes user-controlled input into `static_url()`","plain_action":"","needs_analyst":false,"not_affected_if":["hard-coded-static-paths","tornado-6.6-or-later"],"who_is_affected":"Applications built on Tornado that pass user-controlled strings into static_url() or rely on get_version() with untrusted input. Applications that only use static_url() with hard-coded paths are not exposed to the traversal. unknown whether the sources list other exposure conditions.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000681,"input_tokens":4290,"output_tokens":503,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-123534':14A,17A '-2026':13A,16A '-512':56B,103C '/dev/zero':67B,114C '6.6':70C 'accept':31B 'allow':83C 'app':23B 'attack':43B,84C,93C 'block':59B,116C 'confirm':109C 'contain':71C 'control':45B,94C 'cve':12A,15A 'directori':41B 'event':61B,118C 'exist':53B,111C 'file':8A,36B,52B,87C,107C 'get':29B,80C 'hash':7A,35B,57B,86C,104C 'indefinit':120C 'input':47B,95C 'learn':49B 'loop':62B,119C 'obtain':101C 'outsid':9A,37B,88C 'packag':18B 'pass':96C 'path':2A,11A,40B,73C,90C 'point':64B 'python':19B 'readabl':51B,106C 'refer':113C 'requesthandler.static':26B,77C 'sequenc':32B,92C 'sha':55B,102C 'static':5A,10A,39B,89C,98C 'tornado':1A,20B,24B,68C 'travers':3A,74C 'url':6A,27B,78C,99C 'use':91C 'version':30B,81C 'via':54B 'vulner':75C 'web':22B 'web-app':21B 'whether':50B","nicknames":[],"mitigations":[],"who_affected":"Applications built on Tornado that pass user-controlled strings into static_url() or rely on get_version() with untrusted input. Applications that only use static_url() with hard-coded paths are not exposed to the traversal. unknown whether the sources list other exposure conditions.","tier":"B","verified":{},"analyst_revisit_at":null,"fix_status":"available","audience":"developers","plain_action":null,"pkeys":[],"ptokens":[],"labels":["high","package","python","tornado","webapps"],"campaign_type":null,"search_a":"'-123534':14A,17A '-2026':13A,16A 'cve':12A,15A 'file':8A 'hash':7A 'outsid':9A 'path':2A,11A 'static':5A,10A 'tornado':1A 'travers':3A 'url':6A","search_b":"'-512':56B '/dev/zero':67B 'accept':31B 'app':23B 'attack':43B 'block':59B 'control':45B 'directori':41B 'event':61B 'exist':53B 'file':36B,52B 'get':29B 'hash':35B,57B 'input':47B 'learn':49B 'loop':62B 'outsid':37B 'packag':18B 'path':40B 'point':64B 'python':19B 'readabl':51B 'requesthandler.static':26B 'sequenc':32B 'sha':55B 'static':39B 'tornado':20B,24B 'url':27B 'version':30B 'via':54B 'web':22B 'web-app':21B 'whether':50B","search_c":"'-512':103C '/dev/zero':114C '6.6':70C 'allow':83C 'attack':84C,93C 'block':116C 'confirm':109C 'contain':71C 'control':94C 'event':118C 'exist':111C 'file':87C,107C 'get':80C 'hash':86C,104C 'indefinit':120C 'input':95C 'loop':119C 'obtain':101C 'outsid':88C 'pass':96C 'path':73C,90C 'readabl':106C 'refer':113C 'requesthandler.static':77C 'sequenc':92C 'sha':102C 'static':89C,98C 'tornado':68C 'travers':74C 'url':78C,99C 'use':91C 'version':81C 'vulner':75C","first_public_at":"2026-10-22T13:17:10+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:H/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-2026-123534","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-123534","severity":null,"published_at":"2026-11-08T02:16:43+00:00","modified_at":"2026-11-08T02:16:43+00:00","first_seen_at":"2026-11-08T02:21:10+00:00","fetched_at":"2026-11-08T02:21:10+00:00","note":null}],"documents":[{"id":99217,"url":"https://github.com/tornadoweb/tornado/security/advisories/GHSA-v8g8-cp5j-42fg","title":"Vendor advisory: github.com","kind":"vendor","source":"nvd","publisher":"vendor","text":null,"published_at":"2026-10-22T13:17:10+00:00","relation":"advisory","confidence":null,"note":"Vendor advisory: github.com"},{"id":99218,"url":"https://www.vulncheck.com/advisories/tornado-before-6.6-path-traversal-via-static-url-version-hashing","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"}],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}