Cyber Resilience

CVE-2026-33421

Access Control in Parseplatform Parse-Server ≤ 8.6.53

Access Control
Published
24 March 2026
Modified
25 March 2026
Patch / advisory
View advisory
CVSS Score v4 7.1
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/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 Score 0.0040 32th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-33421 is a high-severity Incorrect Authorization (CWE-863) vulnerability in Parseplatform Parse-Server. Its CVSS base score is 7.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 32th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and AC-4 (Information Flow Enforcement) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.53 and 9.6.0-alpha.42, Parse Server's LiveQuery WebSocket interface does not enforce Class-Level Permission (CLP) pointer permissions (readUserFields and pointerFields).…

more

Any authenticated user can subscribe to LiveQuery events and receive real-time updates for all objects in classes protected by pointer permissions, regardless of whether the pointer fields on those objects point to the subscribing user. This bypasses the intended read access control, allowing unauthorized access to potentially sensitive data that is correctly restricted via the REST API. This issue has been patched in versions 8.6.53 and 9.6.0-alpha.42.

CWE(s)
CWE-863

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1213 Data from Information Repositories Collection
Adversaries may leverage information repositories to mine valuable information.
attack.mitre.org →
Why these techniques?

Authorization bypass in public-facing Parse Server LiveQuery enables exploitation of the application (T1190) to access restricted data objects from the backend repository (T1213).

Confidence: MEDIUM · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-30947Same product: Parseplatform Parse-Server
CVE-2026-34532Same product: Parseplatform Parse-Server
CVE-2026-30854Same product: Parseplatform Parse-Server
CVE-2026-30965Same product: Parseplatform Parse-Server
CVE-2026-29182Same product: Parseplatform Parse-Server
CVE-2026-30228Same product: Parseplatform Parse-Server
CVE-2026-39381Same product: Parseplatform Parse-Server
CVE-2026-31872Same product: Parseplatform Parse-Server
CVE-2026-33527Same product: Parseplatform Parse-Server
CVE-2026-30229Same product: Parseplatform Parse-Server

Affected Assets

parseplatform
parse-server
9.6.0 · ≤ 8.6.53 · 9.0.0 — 9.6.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • AC-3 Access Enforcement
  • AC-4 Information Flow Enforcement
  • AC-6 Least Privilege
Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 5 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

—

Mitigating Controls (NIST 800-53 r5) AI

AC-3 Access Enforcement good match
prevent

Directly enforces class-level pointer permissions on every interface, preventing the LiveQuery WebSocket bypass of readUserFields/pointerFields checks.

AC-4 Information Flow Enforcement good match
prevent

Enforces information-flow rules so that LiveQuery push events cannot deliver object data to subscribers lacking the required pointer relationship.

AC-6 Least Privilege partial match
prevent

Limits each authenticated user to the minimum set of objects permitted by pointer fields, reducing the impact of any LiveQuery enforcement gap.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-05 mostly match
prevents

Defining, enforcing, and reviewing access authorizations and least privilege directly prevents incorrect authorization checks.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.5.15 Access control partial match
prevents

Requiring consistency between access rights and classification plus formal approval steps ensures that the authorization logic correctly distinguishes between entities that should and should not be granted access.

A.5.18 Access rights partial match
prevents

Enforcing policy-driven approval and role-change reviews stops incorrect or stale authorization decisions from remaining in effect after job changes or terminations.

A.8.3 Information access restriction partial match
prevents

By tying access rights to identity, device, location and classification, the control reduces the likelihood that an authorization decision will be based on an incorrect or bypassed policy.

References