{"id":"GHSA-7wqv-xjf3-x35v","summary":"parse-server: Stored XSS via trailing-dot filename bypassing file upload extension blocklist","details":"### Impact\n\nThe 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.\n\n### Patches\n\nA filename ending in a dot is now treated as extensionless. When the parser produces an empty extension, the request handler falls back to validating the Content-Type subtype against the configured extension blocklist, matching the path that already catches truly extensionless uploads with a dangerous Content-Type. This is a follow-up to the previous fix [GHSA-vr5f-2r24-w5hc](https://github.com/parse-community/parse-server/security/advisories/GHSA-vr5f-2r24-w5hc).\n\n### Workarounds\n\nConfigure the storage adapter or CDN to derive Content-Type from the filename extension instead of using the stored Content-Type, or replace the default blocklist with an explicit allowlist of needed file extensions.","aliases":["BIT-parse-2026-53724","CVE-2026-53724"],"modified":"2026-06-19T19:56:23.124647788Z","published":"2026-06-19T19:35:11Z","database_specific":{"severity":"LOW","github_reviewed":true,"github_reviewed_at":"2026-06-19T19:35:11Z","nvd_published_at":"2026-06-12T19:16:30Z","cwe_ids":["CWE-434","CWE-79"]},"references":[{"type":"WEB","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":"WEB","url":"https://github.com/parse-community/parse-server/pull/10489"},{"type":"WEB","url":"https://github.com/parse-community/parse-server/pull/10490"},{"type":"PACKAGE","url":"https://github.com/parse-community/parse-server"}],"affected":[{"package":{"name":"parse-server","ecosystem":"npm","purl":"pkg:npm/parse-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"9.0.0"},{"fixed":"9.9.1-alpha.4"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-7wqv-xjf3-x35v/GHSA-7wqv-xjf3-x35v.json"}},{"package":{"name":"parse-server","ecosystem":"npm","purl":"pkg:npm/parse-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"8.6.79"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 8.6.78","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-7wqv-xjf3-x35v/GHSA-7wqv-xjf3-x35v.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N"}]}