How severe is CVE-2026-33421?

No CVSS score has been assigned to CVE-2026-33421 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-33421?

CVE-2026-33421 affects the following packages: parse-server (npm), parse-server (npm). Ecosystems affected: npm.

How do I fix CVE-2026-33421?

Update parse-server to 9.6.0-alpha.42 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33421 is resolved across your whole dependency graph.

How do I detect CVE-2026-33421 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for parse-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-33421 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2026-33421 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-33421 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-33421?

CVE-2026-33421 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 36th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-33421?

CVE-2026-33421 is classified as CWE-863 (CWE-863). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-33421 published, and has it been updated?

CVE-2026-33421 was published on March 24, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2026-33421 — parse-server

Fix: parse-community/parse-server@6c3317a

CVE-2026-33421 is a CWE-863 vulnerability in parse-server. A fix is available for parse-server — see the affected versions and patch details below.

Parse Server: LiveQuery bypasses CLP pointer permission enforcement

Also known asBIT-parse-2026-33421GHSA-fph2-r4qg-9576

Published

Mar 24, 2026

Updated

Oct 28, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-33421.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs36th percentile — riskier than 36% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

2 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

62other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

parse-servernpm

54Kdownloads / week

Description

Impact

Parse Server's LiveQuery WebSocket interface does not enforce Class-Level Permission (CLP) pointer permissions (readUserFields and pointerFields). 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.

Patches

The LiveQuery server now enforces pointer permissions on each event. After the existing check passes (which defers pointer permissions by design), the fix checks whether any configured pointer field on the object points to the subscribing user. Events for objects that don't match are silently skipped, consistent with how ACL mismatches are handled.

Workarounds

Use ACLs on individual objects to restrict read access instead of relying solely on CLP pointer permissions. ACLs are enforced by LiveQuery.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`parse-server`	≥ 9.0.0&&< 9.6.0-alpha.42	9.6.0-alpha.42`npm install parse-server@9.6.0-alpha.42`
📦npm	`parse-server`	all versions	8.6.53`npm install parse-server@8.6.53`

Affected Products

1 product · 43 configurations

Application

parse-serverparseplatform

≥ 9.0.0 && < 9.6.0

1 version

9.6.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for parse-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update parse-server to 9.6.0-alpha.42 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33421 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

### Impact Parse Server's LiveQuery WebSocket interface does not enforce Class-Level Permission (CLP) pointer permissions (`readUserFields` and `pointerFields`). 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. ### Patches The LiveQuery server now enforce

O3 Security · Impact-Aware SCA

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