{"id":"CVE-2026-100669","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-100669","generatedAt":"2026-10-28T06:34:57.345Z","title":"On IIS running over case-insensitive NTFS, an unauthenticated remote attacker can vary the case of a folder name or file extension (for example GET /user/CONFIG/system.YAML) so that no deny rule matches and the IIS static file handler resolves and…","description":"Grav before 2.0.25 ships web server configuration samples whose access-control deny rules are matched case-sensitively. In webserver-configs/web.config (IIS), every deny rule (user_sensitive_folders, user_accounts, user_data, user_error_redirect, user_pages, system, vendor, ignore_folders) sets ignoreCase=\"false\" on its URL Rewrite <match> element, overriding the IIS default of ignoreCase=\"true\"; because these are rewrite matches rather than <requestFiltering> elements, there is no case-insensitive fallback. On IIS running over case-insensitive NTFS, an unauthenticated remote attacker can vary the case of a folder name or file extension (for example GET /user/CONFIG/system.YAML) so that no deny rule matches and the IIS static file handler resolves and returns the underlying file, disclosing sensitive data such as configuration secrets or account password hashes. Whether a bypassed file is actually returned depends on MIME registration: .json is served by default, while .yaml/.yml return HTTP 404.3 on a stock IIS unless a YAML MIME mapping has been added. The same class of gap exists in the bundled webserver-configs/lighttpd.conf, whose user/(config|env), directory, script-extension, root-file and dotfile rules lack the (?i) modifier, though it is lower risk because lighttpd typically runs on case-sensitive filesystems. Deployments served by Apache (.htaccess), nginx, Caddy, or the PHP built-in server are not affected. The issue is fixed in 2.0.25; because the .htaccess installer heal does not touch web.config or lighttpd.conf, operators must re-copy the corrected sample files after upgrading.","published":"2026-09-26T14:16:50.000Z","lastModified":"2026-09-30T21:16:54.000Z","status":"Deferred","sourceIdentifier":"disclosure@vulncheck.com","cvss":{"version":"4.0","score":8.7,"severity":"HIGH","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/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/M"},"cwe":["CWE-178"],"affected":[],"epss":{"score":0.00443,"percentile":0.38385,"date":"2026-10-27","history":[{"date":"2026-09-27","score":0.00443,"percentile":0.36059}]},"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 (0.44%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[{"kind":"new","label":"New CVE","at":"2026-09-26T14:16:50.000Z","detail":{"score":"8.7","severity":"HIGH","publishedAt":"2026-09-26T14:16:50.427Z"},"summary":"New CVE, high severity (CVSS 8.7)."}],"references":[{"url":"https://github.com/getgrav/grav/security/advisories/GHSA-pg8v-xw58-frq8","source":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/grav-before-2.0.25-sensitive-file-disclosure-via-case-variation-bypass","source":"disclosure@vulncheck.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-100669","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."}