# WebSocket message or subscription authorization failure

A valid connection performs unauthorized per-message actions or receives a private subscription.

**Candidate CWE:** [CWE-862](https://cwe.mitre.org/data/definitions/862.html)

## Test hypothesis

Capture the normal message protocol. Have controlled B subscribe to A’s known private room; A sends one marker. Separately revoke B from a shared room and inspect one subsequent message.

## Evidence required

B receives the unauthorized marker or performs a restricted action. Preserve handshake identity, subscription ID, message sequence, and applicable revocation semantics.

## Rule out false positives

A successful handshake, an ignored subscribe request, or public broadcast messages is not evidence of private channel access.

## Playbook and command references

- [REST, GraphQL, gRPC, WebSocket, and SSE permission parity](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/modules/api-protocols.html) — Carry the same permission invariant across protocols, nested fields, streams, and alternate API versions.
- [Object, function, and property authorization](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/modules/authz-matrix.html) — Turn identities, tenants, objects, roles, and lifecycle transitions into a reproducible permission matrix.
- [Authentication, recovery, federation, and session lifecycle](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/modules/identity-session.html) — Test registration, recovery, identity changes, invitations, SSO enforcement, and deprovisioning as one account state machine.

[Find the associated command snippets](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/commands.html?q=REST%2C%20GraphQL%2C%20gRPC%2C%20WebSocket%2C%20and%20SSE%20permission%20parity)

## Referenced by these target playbooks

[Web & API](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/web-api.html) · [OSS & self-hosted](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/oss.html) · [Mobile](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/mobile.html) · [Desktop & extensions](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/desktop.html) · [AI, agents & MCP](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/ai.html)

## Report checklist

- [ ] Capture the affected version, configuration, identities, and object ownership.
- [ ] Preserve a valid baseline and a negative control.
- [ ] Reproduce the forbidden data access, action, or state change on controlled fixtures.
- [ ] Explain the intended security rule and why the observed behavior violates it.
- [ ] State prerequisites, uncertainty, cleanup, and the smallest demonstrated impact.

## Conditional ATT&CK mapping

No direct ATT&CK mapping selected. Record the weakness and demonstrated impact without forcing an adversary-behavior classification. See the [mapping guide](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/attack.html).

## Primary references

- [OWASP WebSocket security](https://cheatsheetseries.owasp.org/cheatsheets/WebSocket_Security_Cheat_Sheet.html)

[Back to the complete vulnerability catalog](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/vulnerabilities.html)