{"id":"CVE-2026-45118","summary":"MyBB: Contact page reflected XSS","details":"MyBB is free and open source forum software. Prior to 1.8.40, the Contact module does not validate a redirect URL or protocol correctly, resulting in an open redirect and reflected JavaScript code injection. contact.php accepts the redirect target from the from HTTP parameter in $mybb-\u003einput['from'] or the Referer HTTP header in $_SERVER['HTTP_REFERER'] and passes it to redirect() without sufficient verification. A javascript: URI becomes the target of the `Click here if you don't want to wait any longer` link because $force_redirect is true, allowing script execution when a victim selects the link. This issue is fixed in version 1.8.40.","aliases":["GHSA-wf92-5q5h-qr53"],"modified":"2026-09-10T03:30:48.992755262Z","published":"2026-08-18T15:55:27.280Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-83"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45118.json","unresolved_ranges":[{"extracted_events":[{"fixed":"1.8.40"}],"source":"AFFECTED_FIELD"}]},"references":[{"type":"WEB","url":"https://github.com/mybb/mybb/releases/tag/mybb_1840"},{"type":"WEB","url":"https://mybb.com/versions/1.8.40"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45118.json"},{"type":"ADVISORY","url":"https://github.com/mybb/mybb/security/advisories/GHSA-wf92-5q5h-qr53"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-45118"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/mybb/mybb","events":[{"introduced":"0"},{"fixed":"e9942c6d19ac1709b3df7357cfb8810774c8d3ac"}],"database_specific":{"source":"REFERENCES"}}],"versions":["mybb_1839","mybb_1839_build","mybb_1838","mybb_1838_build","mybb_1837","mybb_1837_build","mybb_1836","mybb_1835_build","mybb_1835","mybb_1834","mybb_1834_build","mybb_1833","mybb_1833_build","mybb_1832","mybb_1832_build","mybb_1831","mybb_1831_build","mybb_1829","mybb_1828","mybb_1828_build","mybb_1827_build","mybb_1827","mybb_1823_build","mybb_1823","mybb_1822","mybb_1822_build","mybb_1821pl1","mybb_1821","mybb_1821_build","mybb_1817_build","mybb_1817","mybb_1820","mybb_1820_build","mybb_1820-rc","mybb_1819","mybb_1818","mybb_1819_build","mybb_1818_build","mybb_1816","mybb_1816_build","mybb_1815","mybb_1815_build","mybb_1814","mybb_1813","mybb_1812","mybb_1811","mybb_1810","mybb_1809","mybb_1808","mybb_1807","mybb_1806","mybb_1805","mybb_1804","mybb_1800","mybb_1801"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-45118.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N"}]}