{"id":"CVE-2026-28289","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-28289","generatedAt":"2026-10-31T05:59:58.376Z","title":"A patch bypass vulnerability for CVE-2026-27636 in FreeScout 1.8.206 and earlier allows any authenticated user with file upload permissions to achieve Remote Code Execution (RCE) on the server by uploading a malicious .htaccess file using a zero-width…","description":"FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. A patch bypass vulnerability for CVE-2026-27636 in FreeScout 1.8.206 and earlier allows any authenticated user with file upload permissions to achieve Remote Code Execution (RCE) on the server by uploading a malicious .htaccess file using a zero-width space character prefix to bypass the security check. The vulnerability exists in the sanitizeUploadedFileName() function in app/Http/Helper.php. The function contains a Time-of-Check to Time-of-Use (TOCTOU) flaw where the dot-prefix check occurs before sanitization removes invisible characters. This vulnerability is fixed in 1.8.207.","published":"2026-03-03T23:15:57.000Z","lastModified":"2026-06-17T10:28:26.000Z","status":"Analyzed","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":8.1,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-434"],"affected":["freescout/freescout"],"epss":{"score":0.35103,"percentile":0.98435,"date":"2026-10-30","history":[{"date":"2026-09-24","score":0.02562,"percentile":0.84433},{"date":"2026-10-25","score":0.34935,"percentile":0.98422}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"EPSS puts the probability of exploitation in the next 30 days at 35.1%, higher than 98% of all known CVEs. Patch or mitigate before the next change window."},"changes":[{"kind":"epss","label":"EPSS jump","at":"2026-10-25T00:00:00.000Z","detail":{"to":0.34935,"from":0.0272,"percentile":0.98422},"summary":"EPSS moved from 2.7% to 34.9% probability of exploitation in the next thirty days."},{"kind":"epss","label":"EPSS jump","at":"2026-09-24T00:00:00.000Z","detail":{"to":0.02562,"from":0.3112,"percentile":0.84433},"summary":"EPSS moved from 31.1% to 2.6% probability of exploitation in the next thirty days."}],"references":[{"url":"https://github.com/freescout-help-desk/freescout/commit/f7bc16c56a6b13c06da52ad51fd666546b40818f","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-5gpc-65p8-ffwp","tags":["Exploit","Mitigation","Vendor Advisory"],"source":"security-advisories@github.com"},{"url":"https://www.ox.security/blog/freescout-rce-cve-2026-28289/","tags":["Exploit","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-28289","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}