CVE-2026-55778 PUBLISHED

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.

• https://github.com/parse-community/parse-server/security/advisories/GHSA-v8x7-r927-cc93
• https://github.com/parse-community/parse-server/pull/10505
• https://github.com/parse-community/parse-server/pull/10506
• https://github.com/parse-community/parse-server/commit/97c6a78d19f976ec756c1295f08a8fccab90799a
• https://github.com/parse-community/parse-server/commit/be12a60d65b6e140481882037fb896b1f951df50
• https://github.com/parse-community/parse-server/releases/tag/8.6.81
• https://github.com/parse-community/parse-server/releases/tag/9.9.1-alpha.11

• CWE-434: Unrestricted Upload of File with Dangerous Type CWE