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CVE-2026-34532 — parse-server

Fix: parse-community/parse-server@4fc48cf

CVE-2026-34532 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: Cloud function validator bypass via prototype chain traversal

Also known asBIT-parse-2026-34532GHSA-vpj2-qq7w-5qq6
Published
Updated
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed
Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • A successful exploit gives an attacker total control of the affected component, not partial access.
  • 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-2026-34532.

EPSS Exploitation Probability

via FIRST.org ↗
0.3%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs21th percentile — riskier than 21% of all scored CVEsHighest risk
0.00%0.33%0.66%0.99%0.0%0.3%May 26Sep 26Nov 26

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
81Kdownloads / week

Description

Impact

An attacker can bypass Cloud Function validator access controls by appending .prototype.constructor to the function name in the URL. When a Cloud Function handler is declared using the function keyword and its validator is a plain object or arrow function, the trigger store traversal resolves the handler through its own prototype chain while the validator store fails to mirror this traversal, causing all access control enforcement to be skipped.

This allows unauthenticated callers to invoke Cloud Functions that are meant to be protected by validators such as requireUser, requireMaster, or custom validation logic.

Patches

The trigger store traversal now verifies that each intermediate node is a legitimate store object before continuing traversal. If the traversal encounters a non-store value such as a function handler, it stops and returns an empty store, preventing prototype chain escape.

Workarounds

Use arrow functions instead of the function keyword for Cloud Function handlers. Arrow functions do not have a prototype property and are not affected by this vulnerability.

Resources

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
📦npmparse-server≥ 9.0.0&&< 9.7.0-alpha.119.7.0-alpha.11npm install parse-server@9.7.0-alpha.11
📦npmparse-serverall versions8.6.67npm install parse-server@8.6.67

Affected Products

1 product · 12 configurations
Application
parse-serverparseplatform
≥ 9.0.0 && < 9.7.0
1 version
9.7.0

Detection & mitigation playbook

Open-source dependency

  1. 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.

  2. Fix

    Update parse-server to 9.7.0-alpha.11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-34532 is resolved across your whole dependency graph.

  3. 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 An attacker can bypass Cloud Function validator access controls by appending `.prototype.constructor` to the function name in the URL. When a Cloud Function handler is declared using the `function` keyword and its validator is a plain object or arrow function, the trigger store traversal resolves the handler through its own prototype chain while the validator store fails to mirror this traversal, causing all access control enforcement to be skipped. This allows unauthenticated callers to invoke Cloud Functions that are meant to be protected by validators such as `requireUser`, `re
O3 Security · Impact-Aware SCA

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CVE-2026-34532: parse-server — Fix Available