7.5

CVSS Score

3.1

-

CVSS Score

Basic Information

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CVE-2026-35523

CVE-2026-35523: Authentication bypass in strawberry-graphql via legacy graphql-ws WebSocket subprotocol

Strawberry GraphQL is a library for creating GraphQL APIs. Strawberry up until version 0.312.3 is vulnerable to an authentication bypass on WebSocket subscription endpoints. The legacy graphql-ws subprotocol handler does not verify that a connection_init handshake has been completed before processing start (subscription) messages. This allows a remote attacker to skip the on_ws_connect authentication hook entirely by connecting with the graphql-ws subprotocol and sending a start message directly, without ever sending connection_init. This vulnerability is fixed in 0.312.3.

(GitHub Advisory)

Miggo Vulnerability Database

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CVE-2026-35523

CVE-2026-35523:

7.5

CVSS Score

3.1

-

CVSS Score

Basic Information

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Technical Details

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
strawberry-graphql	pip	<= 0.312.2	0.312.3

Technical Details

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The vulnerability lies in the graphql-ws protocol handler in strawberry-graphql. The analysis of the provided patch 0977a4e6b41b7cfe3e9d8ba84a43458a2b0c54c2 shows that the handle_start method within the GraphQLWSHandler class in strawberry/subscriptions/protocols/graphql_ws/handlers.py was modified. A check was added to ensure that a connection_init message was processed before allowing a subscription to be created. Specifically, a connection_acknowledged flag is now checked at the beginning of handle_start. If this flag is False, the connection is closed with an 'Unauthorized' error. Before this change, an attacker could send a start message over a WebSocket connection using the graphql-ws subprotocol without sending a connection_init message first. This would bypass any authentication logic implemented in the on_ws_connect handler, leading to an authentication bypass.

Vulnerable functions

GraphQLWSHandler.handle_start

strawberry/subscriptions/protocols/graphql_ws/handlers.py

The `handle_start` function in the `GraphQLWSHandler` class is responsible for handling 'start' messages in the legacy `graphql-ws` WebSocket subprotocol. Prior to the patch, this function did not verify that a `connection_init` message had been received and acknowledged. This allowed an attacker to send a 'start' message to create a subscription without any authentication, bypassing the `on_ws_connect` hook.

Vulnerability Intelligence
Miggo AI

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WAF Protection Rules

WAF Rule

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Reasoning

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