{"id":"CVE-2026-114370","kind":"vulnerability","aliases":["CVE-2026-114370"],"related":[],"title":"Undertow: symlink check lets static file requests reach sibling directories","description":"A flaw was found in the PathResourceManager component of the Undertow web server. This component is responsible for serving static files from the file system. The issue occurs because the mechanism used to verify if a symbolic link points to a safe location only checks if the target path starts with a specific string, without ensuring it matches a full directory name. This could allow an attacker to access files in a sibling directory if that directorys name starts with the same characters as an authorized safe directory.","summary":"Undertow's PathResourceManager, which serves static files, checks symbolic link targets by string prefix rather than full directory name. An attacker can read files in a sibling directory whose name starts with the same characters as an allowed directory.","severity":"low","cvss":3.7,"epss":0.00323,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["java","runtime","self-hosted","undertow"],"not_affected_if":["no-static-file-serving","no-symlinks-in-served-dirs"],"how_to_check":"- unknown","fix":null,"status":"open","published_at":"2026-10-21T16:17:33+00:00","first_seen_at":"2026-10-23T21:57:29+00:00","triaged_at":"2026-10-25T04:43:32+00:00","updated_at":"2026-10-25T04:43:32+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-10-25T04:43:32Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"internet","title":"Undertow: symlink check lets static file requests reach sibling directories","impact":"low","summary":"Undertow's PathResourceManager, which serves static files, checks symbolic link targets by string prefix rather than full directory name. An attacker can read files in a sibling directory whose name starts with the same characters as an allowed directory.","category":"runtime","nicknames":[],"who_cares":["java","undertow","self-hosted"],"confidence":0.6,"needs_auth":"no","worst_case":"Attacker reads files from sibling directories on the server","analyst_note":"Find affected Undertow versions and the patched release from the NVD entry at https://nvd.nist.gov/vuln/detail/CVE-2026-114370 and the upstream Undertow advisory.","how_to_check":"- unknown","needs_analyst":true,"not_affected_if":["no-static-file-serving","no-symlinks-in-served-dirs"],"who_is_affected":"Applications running Undertow that serve static files from disk through PathResourceManager and that contain symbolic links pointing into a directory whose name shares a prefix with an allowed one. Deployments that serve no files from disk, or that have no symlinks in served directories, are less exposed. The sources do not give affected versions.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"low"},"cost_usd":0.000576,"input_tokens":3383,"output_tokens":475,"severity_before":"low"},"analyst_status":null,"analyst_note":null,"search":"'-114370':13A,16A '-2026':12A,15A 'access':130C 'allow':60B,126C 'attack':43B,128C 'author':147C 'charact':57B,144C 'check':3A,30B,106C 'compon':69C,76C 'could':125C 'cve':11A,14A 'directori':10A,40B,50B,61B,122C,135C,138C,149C 'ensur':117C 'file':6A,29B,46B,82C,85C,131C 'flaw':63C 'found':65C 'full':39B,121C 'host':21B 'issu':88C 'java':17B 'let':4A 'link':32B,99C 'locat':104C 'match':119C 'mechan':92C 'name':41B,52B,123C,139C 'occur':89C 'path':110C 'pathresourcemanag':25B,68C 'point':100C 'prefix':36B 'rather':37B 'reach':8A 'read':45B 'request':7A 'respons':78C 'runtim':18B 'safe':103C,148C 'self':20B 'self-host':19B 'serv':27B,80C 'server':74C 'sibl':9A,49B,134C 'specif':114C 'start':53B,111C,140C 'static':5A,28B,81C 'string':35B,115C 'symbol':31B,98C 'symlink':2A 'system':86C 'target':33B,109C 'undertow':1A,22B,23B,72C 'use':93C 'verifi':95C 'web':73C 'whose':51B 'without':116C","nicknames":[],"mitigations":[],"who_affected":"Applications running Undertow that serve static files from disk through PathResourceManager and that contain symbolic links pointing into a directory whose name shares a prefix with an allowed one. Deployments that serve no files from disk, or that have no symlinks in served directories, are less exposed. The sources do not give affected versions.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-21T16:17:33+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","cvss_by":"secalert@redhat.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-114370","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-114370","severity":null,"published_at":"2026-10-21T16:17:33+00:00","modified_at":"2026-10-22T15:25:35+00:00","first_seen_at":"2026-10-23T21:57:29+00:00","fetched_at":"2026-10-23T22:29:01+00:00","note":null},{"source":"epss","external_id":"CVE-2026-114370","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-114370","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-24T13:15:54+00:00","fetched_at":"2026-10-24T13:15:54+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}