CVE-2026-55778 — Parse Server: Stored XSS via non-standard file extension bypassing file upload extension blocklist
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to 9.9.1-alpha.11 and 8.6.81, the default fileUpload.fileExtensions…
Published: 2026-07-08 · CVSS: 2.1 · CVSS 4.0
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to 9.9.1-alpha.11 and 8.6.81, the default fileUpload.fileExtensions blocklist could be bypassed by uploading a file with a non-standard or compound extension and dangerous content type, allowing storage adapters such as S3 and GCS to serve attacker-supplied active content and enable stored cross-site scripting. This issue is fixed in versions 9.9.1-alpha.11 and 8.6.81.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7