{"id":"CVE-2026-40487","summary":"Postiz Has Unrestricted File Upload via MIME Type Spoofing that Leads to Stored XSS","details":"Postiz is an AI social media scheduling tool. Prior to version 2.21.6, a file upload validation bypass allows any authenticated user to upload arbitrary HTML, SVG, or other executable file types to the server by spoofing the `Content-Type` header. The uploaded files are then served by nginx with a Content-Type derived from their original extension (`text/html`, `image/svg+xml`), enabling Stored Cross-Site Scripting (XSS) in the context of the application's origin. This can lead to session riding, account takeover, and full compromise of other users' accounts. Version 2.21.6 contains a fix.","aliases":["GHSA-44wg-r34q-hvfx"],"modified":"2026-08-12T03:51:11.591272326Z","published":"2026-04-18T01:19:06.588Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-345","CWE-434","CWE-79"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40487.json"},"references":[{"type":"WEB","url":"https://github.com/gitroomhq/postiz-app/releases/tag/v2.21.6"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40487.json"},{"type":"ADVISORY","url":"https://github.com/gitroomhq/postiz-app/security/advisories/GHSA-44wg-r34q-hvfx"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-40487"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/gitroomhq/postiz-app","events":[{"introduced":"0"},{"fixed":"3ea302202dc0daa3db577eb7c68374cdc1ddbc3c"}],"database_specific":{"cpe":"cpe:2.3:a:gitroom:postiz:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"0"},{"fixed":"2.21.6"}],"source":["AFFECTED_FIELD","CPE_RANGE","REFERENCES"]}}],"versions":["v2.21.5","v2.21.3","v2.21.2","v2.21.1","v2.21.0","v2.20.2","v2.20.1","v2.20.0","v2.19.0","v2.18.0","v2.17.0","v2.16.0","v2.15.1","v2.15.0","v2.14.0","v2.13.0","v2.12.1","v2.12.0","v2.11.3","v2.11.1","v2.11.0","v2.10.1","v2.10.0","v2.9.0","v2.8.3","v2.8.2","v2.8.1","v2.8.0","v2.7.0","v2.6.4","v2.6.3","v2.6.2","v2.6.1","v2.5.4","v2.5.3","v2.4.3","v2.5.2","v2.5.1","v2.5.0","v2.4.2","v2.4.1","v2.4.0","v2.3.1","v2.3.0","v2.2.5","v2.2.4","v2.2.3","v2.2.1","v2.2.0","v2.1.2","v2.1.1","v2.0.8","v2.0.7","v2.0.6","v2.0.5","v2.0.4","v2.0.3","v2.0.2","v2.0.1","v1.65.7","v1.65.6","v1.65.5","v1.65.4","v1.65.3","v1.65.2","v1.65.1","v1.65.0","v1.64.1","v1.64.0","v1.63.0","v1.62.3","v1.62.2","v1.62.1","v1.62.0","v1.61.2","v1.61.0","v1.60.1","v1.60.0","v1.59.0","v1.58.0","v1.57.0","v1.56.0","v1.55.5","v1.54.0","v1.55.4","v1.55.3","v1.55.2","v1.55.1","v1.55.0","v1.54.1","v1.53.0","v1.52.2","v1.52.1","v1.52.0","v1.51.0","v1.50.0","v1.49.1","v1.49.0","v1.48.4","v1.48.3","v1.48.2","v1.48.1","v1.47.0","v1.45.1","v1.44.2","v1.44.1","v1.43.5","v1.43.4","v1.43.3","v1.43.2","v1.43.1","v1.43.0","v1.41.1","v1.41.0","v1.40.1","v1.40.0","v1.39.3","v1.39.2","v1.38.2","v1.38.1","v1.37.4","v1.37.3","v1.37.2","v1.37.1","v1.36.1","v1.35.1","v1.34.1","v1.33.2","v1.33.1","v1.32.1","v1.31.1","v1.30.1","v1.29.1","v1.28.1","v1.27.2","v1.26.1","v1.24.1","v1.23.2","v1.23.1","v1.22.1","v1.10.1","v1.10.0","v1.8.1","v1.7.12","v1.6.12","v1.6.9","v1.6.4","v1.6.2","v1.6.1","1.6.0","v1.5.0","v1.4.0","v1.3.0","v1.2.0","v1.1.0","v1.0.0","v0.0.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-40487.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L"}]}