# CVE-2026-35526: Strawberry GraphQL Denial of Service via unbounded WebSocket subscriptions

Source: https://junglewise.ai/threats/cve-2026-35526-strawberry-graphql-denial-of-service-via-unbounded-websocket  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-07. Updated: 2026-06-08  
License: CC BY 4.0 with a link back

CVE-2026-35526 · Severity: high · CVSS 7.5 · Published 2026-04-07

Strawberry GraphQL is a library used to build GraphQL APIs in Python. A vulnerability in its WebSocket handling allows an unauthenticated attacker to crash the server or cause significant performance slowdowns by flooding it with subscription requests. This can lead to a total service outage, preventing legitimate users from accessing the application.

Technologies: [strawberry-graphql (PyPI)](https://junglewise.ai/threats/technologies/strawberry-graphql). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2026-35526 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-35526 being exploited in the wild.

**How severe is CVE-2026-35526?** High severity, with a CVSS score of 7.5, published 7 April 2026.

**Which products and versions are affected?** strawberry-graphql (PyPI) <= 0.312.2, ECOSYSTEM:introduced=0,fixed=0.312.3.

**Is there a fix for CVE-2026-35526?** Yes. strawberry-graphql (PyPI): upgrade to 0.312.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-35526 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-35526?** Check whether you run strawberry-graphql (PyPI) or Strawberry Graphql at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- strawberry-graphql (PyPI): upgrade to 0.312.3 or later

  ```sh
  pip install "strawberry-graphql>=0.312.3"
  ```


## Technical details

Strawberry GraphQL's WebSocket subscription handlers for both `graphql-transport-ws` and the legacy `graphql-ws` protocols fail to enforce limits on the number of active subscriptions per connection. An unauthenticated remote attacker can initiate a WebSocket connection and flood the server with 'subscribe' messages containing unique IDs. Each message triggers the allocation of an `asyncio.Task` and an `Operation` object, leading to linear memory growth and event loop saturation. This results in an Out-of-Memory (OOM) crash or severe server degradation. The issue is fixed in version 0.312.3.

## Affected products

- strawberry-graphql strawberry-graphql <= 0.312.2

## Identifiers

- CVE-2026-35526
- GHSA-hv3w-m4g2-5x77
- PYSEC-2026-134

## Timeline

- 2026-04-04: disclosed: Initial disclosure by patrick91
- 2026-04-06: advisory: GitHub Advisory published
- 2026-04-07: other: NVD published CVE-2026-35526

## References

- [https://api.github.com/users/JFOZ1010](https://api.github.com/users/JFOZ1010)
- [https://github.com/JFOZ1010](https://github.com/JFOZ1010)
- [https://api.github.com/users/JFOZ1010/gists%7B/gist_id%7D](https://api.github.com/users/JFOZ1010/gists%7B/gist_id%7D)
- [https://api.github.com/users/JFOZ1010/repos](https://api.github.com/users/JFOZ1010/repos)
- [https://avatars.githubusercontent.com/u/82562585?v=4](https://avatars.githubusercontent.com/u/82562585?v=4)
- [https://api.github.com/users/JFOZ1010/events%7B/privacy%7D](https://api.github.com/users/JFOZ1010/events%7B/privacy%7D)

## Related threats

- [Strawberry GraphQL permission check bypass via awaitable return value](https://junglewise.ai/threats/cve-2026-107728-strawberry-graphql-synchronous-permission-checks-can-treat-an)
- [Strawberry legacy graphql-ws retains naturally completed subscription slots](https://junglewise.ai/threats/cve-2026-107727-strawberry-legacy-graphql-ws-retains-naturally-completed)
- [PYSEC-2026-1946 - Strawberry GraphQL has type resolution vulnerability in node interface that allows potential data…](https://junglewise.ai/threats/cve-2025-22151-strawberry-graphql-has-type-resolution-vulnerability-in-node)
- [Strawberry GraphQL DoS via MaxAliasesLimiter bypass in FragmentSpreadNode](https://junglewise.ai/threats/cve-2026-47707-strawberry-graphql-dos-via-maxaliaseslimiter-bypass-in)
- [Strawberry GraphQL Denial of Service via Uncontrolled Recursion in QueryDepthLimiter](https://junglewise.ai/threats/cve-2026-47706-strawberry-graphql-denial-of-service-via-uncontrolled-recursion)