{"id":"GHSA-9c3j-xm6v-j7j3","aliases":["CVE-2026-40597"],"title":"MantisBT has a Content Security Policy bypass via attachments","titleSource":"OSV","descriptionSource":"OSV","declaredSeverity":"HIGH","description":"Given any pre-existing XSS / HTML injection vulnerability, an attacker can bypass the Content Security Policy's _script-src_ directive by uploading a crafted attachment to any issue that, when accessed via the _file_download.php_ link, will be downloaded with a valid JavaScript MIME type resulting in script execution.\n\nThe uploaded payload must be sniffed as a valid JavaScript MIME type by PHP finfo (see file_create_finfo() API function). Non-JavaScript MIME types will not get imported in a `<script>` tag by the browser, due to response header X-Content-Type-Options being set to _nosniff_, which requires all imported JavaScript files to be a valid JavaScript MIME type.\n\n### Impact\nCross-site scripting\n\n### Patches\n- 9e3bee2e7b909f4e3596985892b8bc8bee9e0bfe\n\n### Workarounds\nNone\n\n### Credits\nThanks to siunam (Tang Cheuk Hei) for discovering and responsibly reporting the issue.","severity":"high","score":7.6,"published":"2026-05-11T19:34:48.000Z","modified":"2026-09-10T03:51:05.076Z","withdrawn":false,"knownExploited":false,"affected":[{"ecosystem":"Packagist","name":"mantisbt/mantisbt","sources":[{"name":"OSV · GHSA-9c3j-xm6v-j7j3","url":"https://osv.dev/vulnerability/GHSA-9c3j-xm6v-j7j3"}],"ranges":[{"events":[{"introduced":"0"},{"fixed":"2.28.2"}],"type":"ECOSYSTEM"}],"versions":["2.10.0","2.10.1","2.11.0","2.11.1","2.12.0","2.12.1","2.12.2","2.13.0","2.13.1","2.13.2","2.14.0","2.15.0","2.15.1","2.16.0","2.16.1","2.17.0","2.17.1","2.17.2","2.18.0","2.18.1","2.19.0","2.19.1","2.20.0","2.20.1","2.21.0","2.21.1","2.21.2","2.21.3","2.22.0","2.22.1","2.22.2","2.23.0","2.23.1","2.24.0","2.24.1","2.24.2","2.24.3","2.24.4","2.24.5","2.25.0","2.25.1","2.25.2","2.25.3","2.25.4","2.25.5","2.25.6","2.25.7","2.25.8","2.26.0","2.26.1","2.26.2","2.26.3","2.26.4","2.27.0","2.27.1","2.27.2","2.27.3","2.28.0","2.28.1","2.3.0","2.3.1","2.3.2","2.3.3","2.4.0","2.4.1","2.4.2","2.5.0","2.5.1","2.5.2","2.6.0","2.7.0","2.7.1","2.8.0","2.8.1","2.9.0","2.9.1"],"fixed":["2.28.2"]}],"sourceAffected":[],"references":["https://github.com/mantisbt/mantisbt/security/advisories/GHSA-9c3j-xm6v-j7j3","https://nvd.nist.gov/vuln/detail/CVE-2026-40597","https://github.com/mantisbt/mantisbt/commit/9e3bee2e7b909f4e3596985892b8bc8bee9e0bfe","https://github.com/mantisbt/mantisbt","https://mantisbt.org/bugs/view.php?id=37016"],"sources":[{"name":"OSV","id":"GHSA-9c3j-xm6v-j7j3","modified":"2026-09-10T03:51:05.076582633Z","url":"https://osv.dev/vulnerability/GHSA-9c3j-xm6v-j7j3"}],"assessments":[{"source":"OSV","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N","score":7.6}],"products":[],"remediation":[],"kev":{"status":"not-listed","checkedAt":"2026-10-28T19:20:37.165Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[]}