What is the CVSS score of CVE-2026-35523?

CVE-2026-35523 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. EPSS exploitation probability: 0.1%.

How to fix or mitigate CVE-2026-35523?

Within 24 hours: Identify all deployments running Strawberry GraphQL versions <0.312.3 using dependency scanners (pip, npm, or equivalent). Within 7 days: Upgrade to Strawberry GraphQL version 0.312.3 or later across all affected systems and validate the deployment in a staging environment. Within 30 days: Audit access logs for WebSocket subscription endpoints to identify any unauthorized access attempts and review subscription data retention policies.

CVE-2026-35523

HIGH

Missing Authentication for Critical Function (CWE-306)

2026-04-06 https://github.com/strawberry-graphql/strawberry

GHSA-vpwc-v33q-mq89

Authentication Bypass

7.5

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

7.5 HIGH

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Lifecycle Timeline

Re-analysis Queued

Apr 17, 2026 - 20:52 vuln.today

cvss_changed

Analysis Generated

Apr 06, 2026 - 19:00 vuln.today

Patch released

Apr 06, 2026 - 19:00 nvd

Patch available

CVE Published

Apr 06, 2026 - 18:00 nvd

HIGH 7.5

DescriptionGitHub Advisory

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.

The graphql-transport-ws subprotocol handler is not affected, as it correctly gates subscription operations on a connection_acknowledged flag. However, both subprotocols are enabled by default in all framework integrations that support websockets, and the subprotocol is selected by the client via the Sec-WebSocket-Protocol header.

Any application relying on on_ws_connect for authentication or authorization is affected.

Mitigation: Upgrade to the patched version, or explicitly disable the legacy graphql-ws subprotocol by setting subscription_protocols=[GRAPHQL_TRANSPORT_WS_PROTOCOL] on your GraphQL view/router.

AnalysisAI

Authentication bypass in Strawberry GraphQL WebSocket subscriptions (versions <0.312.3) allows unauthenticated remote attackers to access protected GraphQL subscription endpoints by exploiting the legacy graphql-ws subprotocol handler. Attackers can skip the on_ws_connect authentication hook by connecting with graphql-ws and sending subscription start messages without completing the connection_init handshake. No public exploit identified at time of analysis, though exploitation is straightforward given the protocol-level nature of the bypass. CVSS 7.5 reflects network-accessible unauthenticated attack with high confidentiality impact.

Technical ContextAI

Strawberry is a Python GraphQL library (pkg:pip/strawberry-graphql) that supports WebSocket-based GraphQL subscriptions via two subprotocols: the legacy graphql-ws and the newer graphql-transport-ws. The vulnerability stems from improper access control (CWE-306) in the graphql-ws handler implementation. In a correct WebSocket subscription flow, clients must complete a connection_init handshake before the server processes subscription operations. The graphql-transport-ws handler enforces this via a connection_acknowledged flag that gates subsequent messages. However, the legacy graphql-ws handler fails to verify handshake completion before processing start messages, allowing clients to bypass the on_ws_connect authentication hook entirely. Because both subprotocols are enabled by default across all framework integrations (ASGI, Django, FastAPI, etc.) and clients select the protocol via the Sec-WebSocket-Protocol HTTP header, attackers can trivially force use of the vulnerable handler regardless of server configuration preferences.

RemediationAI

Vendor-released patch: version 0.312.3 (released at https://github.com/strawberry-graphql/strawberry/releases/tag/0.312.3). Upgrade strawberry-graphql to version 0.312.3 or later via pip install --upgrade strawberry-graphql to apply the fix implemented in commit 0977a4e6b41b7cfe3e9d8ba84a43458a2b0c54c2. For environments where immediate upgrade is not feasible, explicitly disable the vulnerable legacy graphql-ws subprotocol by configuring subscription_protocols=[GRAPHQL_TRANSPORT_WS_PROTOCOL] on GraphQL view or router instances, forcing clients to use only the secure graphql-transport-ws protocol. Review application logs for suspicious WebSocket connection patterns where start messages appear without preceding connection_init messages, particularly connections specifying graphql-ws in Sec-WebSocket-Protocol headers. Consult the GitHub security advisory at https://github.com/strawberry-graphql/strawberry/security/advisories/GHSA-vpwc-v33q-mq89 for additional vendor guidance.