Vulnerability · Published Jun 12, 2026 · Assigned by GitHub_M
CVE-2026-53724Parse Server: Stored XSS via trailing-dot filename bypassing file upload extension blocklist
Low 2.1
In plain English
A low-severity unrestricted file upload in parse-server from parse-community. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 21% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | parse-server | 9.9.1-alpha.4 | GHSA-7wqv-xjf3-x35v |
| npm | parse-server | 8.6.79 | GHSA-7wqv-xjf3-x35v |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| parse-community | parse-server | < 8.6.79>= 9.0.0, < 9.9.1-alpha.4 |
Weakness: CWE-434, CWE-79 · Vector: 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
References
- https://github.com/parse-community/parse-server/security/advisories/GHSA-7wqv-xjf3-x35v x_refsource_CONFIRM
- https://github.com/parse-community/parse-server/pull/10489 x_refsource_MISC
- https://github.com/parse-community/parse-server/pull/10490 x_refsource_MISC