CVE-2026-55778
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…
Does this matter?
Lower severity and a low EPSS score (0.55%). Track it; it rarely justifies an emergency change on its own.
Description
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.
- CVSS 4.0
- 2.1 LOWCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.55% probability · 45th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-434
- Source
- security-advisories@github.com
References
- 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/pull/10505
- https://github.com/parse-community/parse-server/pull/10506
- 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
- https://github.com/parse-community/parse-server/security/advisories/GHSA-v8x7-r927-cc93
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.