{"id":"CVE-2026-8134","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-8134","generatedAt":"2026-10-28T02:11:07.995Z","title":"Concrete CMS 9.5.0 and below fails to sanitize path traversal sequences in the ptComposerFormLayoutSetControlCustomTemplate field when saving page type composer form layouts.","description":"Concrete CMS 9.5.0 and below fails to sanitize path traversal sequences in the ptComposerFormLayoutSetControlCustomTemplate field when saving page type composer form layouts. An authenticated rogue administrator with composer form editing rights can exploit this to include arbitrary readable files on the server. Combined with the file uploader's extension-only validation (which permits PHP code in files saved with image extensions like .png), this can result in authenticated remote code execution. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 9.4 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H   Thanks Yonatan Drori (Tenzai) for reporting.","published":"2026-05-21T21:16:33.000Z","lastModified":"2026-07-23T16:10:00.000Z","status":"Analyzed","sourceIdentifier":"ff5b8ace-8b95-4078-9743-eac1ca5451de","cvss":{"version":"4.0","score":9.4,"severity":"CRITICAL","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-23","CWE-98","CWE-434"],"affected":["concretecms/concrete cms"],"epss":{"score":0.00739,"percentile":0.54299,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.74%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes","tags":["Release Notes"],"source":"ff5b8ace-8b95-4078-9743-eac1ca5451de"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-8134","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."}