{"schemaVersion":3,"id":"CVE-2026-111053","aliases":[],"status":"published","duplicateOf":null,"title":"FOSSBilling: Unauthenticated attacker can probe existence of arbitrary files via guest/system/template_exists","description":"FOSSBilling is an open source billing and client-management platform. From 0.1.0 until 0.8.7, the unauthenticated api/guest/system/template_exists endpoint permits path traversal because templateExists uses Path::join on the attacker-controlled file parameter without rejecting .. sequences or verifying that the resolved path remains inside the active theme directory. The trigger is an unauthenticated request to guest/system/template_exists containing traversal sequences in the file parameter. An attacker can submit traversal sequences in the file parameter and observe the returned boolean to determine whether arbitrary files or directories exist on the server. The oracle does not disclose file contents. This issue is fixed in version 0.8.7.","dates":{"published":"2026-10-19T15:54:17.610Z","modified":"2026-10-19T16:36:49.366Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":6.9,"severity":"medium","version":"4.0","versionLabel":"v4.0","source":"CVE.org","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N","computed":false,"selection":"backend-summary"},"metrics":[{"version":"4.0","versionLabel":"v4.0","source":"CVE.org","score":6.9,"severity":"medium","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N","exploitability":null,"impact":null,"computed":false},{"version":"4.0","versionLabel":"v4.0","source":"NVD","score":6.9,"severity":"medium","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/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","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.00368,"percentile":0.29506,"severity":"low","asOf":"2026-10-22T00:00:00.000Z","change":{"pp":null,"baselineDate":null,"baselineScore":null},"history":[{"date":"2026-10-20T00:00:00.000Z","score":0.00368,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.00368,"percentile":null},{"date":"2026-10-22T00:00:00.000Z","score":0.00368,"percentile":0.29506}],"last30":[{"date":"2026-10-20T00:00:00.000Z","score":0.00368,"percentile":null},{"date":"2026-10-21T00:00:00.000Z","score":0.00368,"percentile":null},{"date":"2026-10-22T00:00:00.000Z","score":0.00368,"percentile":0.29506}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[],"exploitCount":0,"weaknesses":[{"id":"CWE-22","name":"Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')","description":"The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.","type":"weakness","status":"Stable","abstraction":"Base","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/22.html"},{"id":"CWE-200","name":"Exposure of Sensitive Information to an Unauthorized Actor","description":"The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.","type":"weakness","status":"Draft","abstraction":"Class","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/200.html"}],"affected":[{"vendor":"fossbilling","product":"fossbilling","name":"FOSSBilling","label":"fossbilling","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ 0.1.0, < 0.8.7","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 0.1.0, < 0.8.7","eol":null,"hubHref":"/vendor/fossbilling/fossbilling"}],"affectedCount":1,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-fm3x-cx5r-wwgp","label":"github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-fm3x-cx5r-wwgp","hostname":"github.com","tags":["X Refsource CONFIRM"]},{"url":"https://github.com/FOSSBilling/FOSSBilling/pull/4221","label":"github.com/FOSSBilling/FOSSBilling/pull/4221","hostname":"github.com","tags":["X Refsource MISC"]},{"url":"https://github.com/FOSSBilling/FOSSBilling/commit/e6ca7731c6bce406aba11900a4450e89c4ebdb01","label":"github.com/FOSSBilling/FOSSBilling/commit/e6ca7731c6bce406aba11900a4450e89c4ebdb01","hostname":"github.com","tags":["X Refsource MISC"]},{"url":"https://github.com/FOSSBilling/FOSSBilling/releases/tag/0.8.7","label":"github.com/FOSSBilling/FOSSBilling/releases/tag/0.8.7","hostname":"github.com","tags":["X Refsource MISC"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2026-10-19T15:54:17.610Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-10-19T16:36:49.366Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":28,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-22T21:15:03.142Z","stale":false,"partial":false}}