{"id":"CVE-2026-53724","aliases":["BIT-parse-2026-53724","GHSA-7wqv-xjf3-x35v"],"url":"https://o3.security/vulnerability/CVE-2026-53724","summary":"Parse Server: Stored XSS via trailing-dot filename bypassing file upload extension blocklist","details":"Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.79 and 9.9.1-alpha.4, the default file upload extension blocklist can be bypassed by appending a trailing dot to a filename whose extension would otherwise be blocked (e.g. poc.svg.). The trailing dot causes the extension parser to extract an empty string, which short-circuits the blocklist check, and the attacker-controlled Content-Type is forwarded to the storage adapter unchanged. Storage adapters that persist and serve the provided Content-Type (such as S3 or GCS) then serve the file with an active type such as image/svg+xml, enabling stored XSS when a victim opens the file URL. The default GridFS adapter is not affected because it sets X-Content-Type-Options: nosniff on responses. This issue has been patched in versions 8.6.79 and 9.9.1-alpha.4.","published":"2026-06-12T18:34:38.237Z","modified":"2026-08-12T03:51:09.002672Z","cvss":null,"epss":{"score":0.00281,"percentile":0.20322,"asOf":"2026-09-07"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"parse-server","fixedVersion":"9.9.1-alpha.4"},{"ecosystem":"npm","name":"parse-server","fixedVersion":"8.6.79"}],"fix":{"url":"https://github.com/parse-community/parse-server/pull/10489","label":"parse-community/parse-server#10489"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53724.json"},{"type":"ADVISORY","url":"https://github.com/parse-community/parse-server/security/advisories/GHSA-7wqv-xjf3-x35v"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53724"},{"type":"FIX","url":"https://github.com/parse-community/parse-server/pull/10489"},{"type":"FIX","url":"https://github.com/parse-community/parse-server/pull/10490"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:09.002672Z"}}