{"id":"CVE-2026-45125","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-45125","generatedAt":"2026-10-28T04:36:02.301Z","title":"Prior to 1.8.40, the Email User controller does not sanitize sender names correctly, resulting in mail header injection. member.php?action=do_emailuser accepts the fromname HTTP parameter for guests or the stored username for authenticated users when…","description":"MyBB is free and open source forum software. Prior to 1.8.40, the Email User controller does not sanitize sender names correctly, resulting in mail header injection. member.php?action=do_emailuser accepts the fromname HTTP parameter for guests or the stored username for authenticated users when the cansendemail group permission is enabled. When mail_handler is set to the default PHP mail value, the sender name is used without sanitization in Return-Path and Reply-To headers, allowing arbitrary headers to be injected with CRLF sequences. This issue is fixed in version 1.8.40.","published":"2026-08-18T16:17:08.000Z","lastModified":"2026-09-08T21:02:26.000Z","status":"Deferred","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"},"cwe":["CWE-93"],"affected":[],"epss":{"score":0.00412,"percentile":0.35244,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.41%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://github.com/mybb/mybb/commit/5046c56b515d4593297a4f65b0c6ccb0b55baa01","source":"security-advisories@github.com"},{"url":"https://github.com/mybb/mybb/releases/tag/mybb_1840","source":"security-advisories@github.com"},{"url":"https://github.com/mybb/mybb/security/advisories/GHSA-f626-53q9-pqm9","source":"security-advisories@github.com"},{"url":"https://mybb.com/versions/1.8.40","source":"security-advisories@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-45125","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."}