Strawberry GraphQL is a library for creating GraphQL APIs. Prior to 0.312.3, Strawberry GraphQL's WebSocket subscription handlers for both the graphql-transport-ws and legacy graphql-ws protocols allocate an asyncio.Task and associated Operation object for every incoming subscribe message without enforcing any limit on the number of active subscriptions per connection. An unauthenticated attacker can open a single WebSocket connection, send connection_init, and then flood subscribe messages with unique IDs. Each message unconditionally spawns a new asyncio.Task and async generator, causing linear memory growth and event loop saturation. This leads to server degradation or an OOM crash. This vulnerability is fixed in 0.312.3.

Project Subscriptions

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-hv3w-m4g2-5x77 strawberry-graphql: Denial of Service via unbounded WebSocket subscriptions
Fixes

Solution

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Workaround

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History

Tue, 07 Apr 2026 18:00:00 +0000

Type Values Removed Values Added
Description Strawberry GraphQL is a library for creating GraphQL APIs. Prior to 0.312.3, Strawberry GraphQL's WebSocket subscription handlers for both the graphql-transport-ws and legacy graphql-ws protocols allocate an asyncio.Task and associated Operation object for every incoming subscribe message without enforcing any limit on the number of active subscriptions per connection. An unauthenticated attacker can open a single WebSocket connection, send connection_init, and then flood subscribe messages with unique IDs. Each message unconditionally spawns a new asyncio.Task and async generator, causing linear memory growth and event loop saturation. This leads to server degradation or an OOM crash. This vulnerability is fixed in 0.312.3.
Title Strawberry GraphQL affected by a Denial of Service via unbounded WebSocket subscriptions
Weaknesses CWE-770
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-04-07T15:23:36.548Z

Reserved: 2026-04-03T02:15:39.281Z

Link: CVE-2026-35526

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-04-07T16:16:28.843

Modified: 2026-04-07T16:16:28.843

Link: CVE-2026-35526

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses