CVE-2026-33538

Description

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.58 and 9.6.0, an unauthenticated attacker can cause denial of service by sending authentication requests with arbitrary, unconfigured provider names. The server executes a database query for each unconfigured provider before rejecting the request, and since no database index exists for unconfigured providers, each request triggers a full collection scan on the user database. This can be parallelized to saturate database resources. This issue has been patched in versions 8.6.58 and 9.6.0

How to fix CVE-2026-33538

To remediate CVE-2026-33538, upgrade the affected package to a fixed version below.

• —upgrade to 8.6.58 or later
• —upgrade to 9.6.0-alpha.52 or later

Is CVE-2026-33538 being exploited?

Low — EPSS is 0.4%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• from 0, < 8.6.58, >= 9.0.0, < 9.6.0
• >= 9.0.0, < 9.6.0-alpha.52

CVSS scores

References (7)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2026-33538
• PATCHgithub.com/parse-community/parse-server
• WEBgithub.com/parse-community/parse-server/commit/40eb442e02672986730007d0a1edb22c1c4bd357
• WEBgithub.com/parse-community/parse-server/commit/fbac847499e57f243315c5fc7135be1d58bb8e54