{"id":"CVE-2026-100523","aliases":["EUVD-2026-87378","GHSA-g8jm-3grw-8wh2"],"status":"published","title":"Cotonti through 1.0.0 Open Redirect via message.php redirect parameter","description":"Cotonti through 1.0.0 contains an open redirect vulnerability in message.php that base64-decodes the redirect parameter without domain validation. Unauthenticated attackers can craft malicious links with encoded external URLs to redirect users to arbitrary sites via meta refresh tags for phishing attacks.","severity":{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00188,"percentile":0.08454,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-601"],"published":"2026-09-26T00:59:24Z","modified":"2026-10-28T02:30:28Z","products":[{"vendor":"cotonti","product":"cotonti"}],"references":[{"url":"https://github.com/Cotonti/Cotonti/issues/1907","tags":["issue-tracking","report"]},{"url":"https://github.com/Cotonti/Cotonti/pull/1908","tags":["issue-tracking","patch","fix"]},{"url":"https://github.com/Cotonti/Cotonti/blob/1.0.0/message.php","tags":["technical-description","article"]},{"url":"https://github.com/Cotonti/Cotonti/blob/1.0.0/system/common.php","tags":["technical-description","article"]},{"url":"https://github.com/Cotonti/Cotonti","tags":["product","package"]},{"url":"https://www.vulncheck.com/advisories/cotonti-through-1.0.0-open-redirect-via-message-php-redirect-parameter","tags":["third-party-advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-100523","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-g8jm-3grw-8wh2"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/100xxx/CVE-2026-100523.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-100523","title":"Cotonti through 1.0.0 Open Redirect via message.php redirect parameter","description":"Cotonti through 1.0.0 contains an open redirect vulnerability in message.php that base64-decodes the redirect parameter without domain validation. Unauthenticated attackers can craft malicious links with encoded external URLs to redirect users to arbitrary sites via meta refresh tags for phishing attacks.","status":"published","published":"2026-09-26T00:59:24.331Z","modified":"2026-10-05T14:55:04.892Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"medium","assessor":"cna"},{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-601"],"updated_at":"2026-11-02T14:20:06.925367Z"}],"euvd":[{"id":"EUVD-2026-87378","description":"Cotonti through 1.0.0 contains an open redirect vulnerability in message.php that base64-decodes the redirect parameter without domain validation. Unauthenticated attackers can craft malicious links with encoded external URLs to redirect users to arbitrary sites via meta refresh tags for phishing attacks.","status":"published","published":"2026-09-26T00:59:24Z","modified":"2026-10-05T14:55:04Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"medium"}],"updated_at":"2026-11-02T17:27:39.819382Z"}],"ghsa":[{"id":"GHSA-g8jm-3grw-8wh2","title":"Cotonti through 1.0.0 contains an open redirect vulnerability in message.php that base64-decodes...","description":"Cotonti through 1.0.0 contains an open redirect vulnerability in message.php that base64-decodes the redirect parameter without domain validation. Unauthenticated attackers can craft malicious links with encoded external URLs to redirect users to arbitrary sites via meta refresh tags for phishing attacks.","status":"published","published":"2026-09-26T03:30:22Z","modified":"2026-09-26T03:30:23Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"},{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/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","level":"medium"}],"cwes":["CWE-601"],"updated_at":"2026-11-02T15:12:29.177042Z"}],"nvd":[{"id":"CVE-2026-100523","description":"Cotonti through 1.0.0 contains an open redirect vulnerability in message.php that base64-decodes the redirect parameter without domain validation. Unauthenticated attackers can craft malicious links with encoded external URLs to redirect users to arbitrary sites via meta refresh tags for phishing attacks.","status":"published","published":"2026-09-26T01:17:00.87Z","modified":"2026-10-05T15:17:10.117Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/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","level":"medium","assessor":"secondary"},{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-601"],"updated_at":"2026-11-02T14:12:51.721923Z"}],"osv":[{"id":"CVE-2026-100523","title":"Cotonti through 1.0.0 Open Redirect via message.php redirect parameter","description":"Cotonti through 1.0.0 contains an open redirect vulnerability in message.php that base64-decodes the redirect parameter without domain validation. Unauthenticated attackers can craft malicious links with encoded external URLs to redirect users to arbitrary sites via meta refresh tags for phishing attacks.","status":"published","published":"2026-09-26T00:59:24.331Z","modified":"2026-10-28T02:30:28.757158956Z","cvss":[{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"medium"}],"cwes":["CWE-601"],"updated_at":"2026-11-02T15:44:53.490346Z"}]}}