CVE-2026-33538: 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-alpha.52, a...

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-alpha.52, 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-alpha.52.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS 4.0

8.7/10

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.41%

32.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-400

Affected Software

Vendor	Product	Versions	Update
Parseplatform	Parse-Server	< 8.6.58	—
Parseplatform	Parse-Server	>= 9.0.0, < 9.6.0	—
Parseplatform	Parse-Server	9.6.0	Alpha1

References

Timeline

Published: Mar 24, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-33538?

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-alpha.52, 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-alpha.52.

How severe is CVE-2026-33538?

CVE-2026-33538 has a CVSS score of 8.7/10 (HIGH severity). The EPSS model estimates a 0.41% probability of exploitation in the next 30 days.

How do I fix CVE-2026-33538?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.