{"id":"CVE-2026-100523","title":"Cotonti through 1.0.0 contains an open redirect vulnerability in message.php that base64-decodes the redirect parameter without domain validation","summary":"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…","severity":"medium","cvss":6.1,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","cwe":["CWE-601"],"vendor":"Cotonti","product":"Cotonti","affected":["Cotonti <= 1.0.0"],"published":"2026-09-26","updated":"2026-10-05","sourceUpdated":"2026-10-05T15:17:10.117","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-100523","references":[{"url":"https://github.com/Cotonti/Cotonti","label":"disclosure@vulncheck.com"},{"url":"https://github.com/Cotonti/Cotonti/blob/1.0.0/message.php","label":"disclosure@vulncheck.com"},{"url":"https://github.com/Cotonti/Cotonti/blob/1.0.0/system/common.php","label":"disclosure@vulncheck.com"},{"url":"https://github.com/Cotonti/Cotonti/issues/1907","label":"disclosure@vulncheck.com"},{"url":"https://github.com/Cotonti/Cotonti/pull/1908","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/cotonti-through-1.0.0-open-redirect-via-message-php-redirect-parameter","label":"disclosure@vulncheck.com"}],"tags":["nvd","cve.org"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-05T14:01:31.542603Z"},"epss":0.00188,"epssPercentile":0.08285,"ingestedAt":"2026-09-26T01:24:36.887Z","slug":"CVE-2026-100523","body":"## Overview\n\nCotonti 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":34,"depthScoreParts":{"impact":33.6,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}