strawberry-graphql: Denial of Service via unbounded WebSocket subscriptions
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.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | strawberry-graphql | < 0.312.3 | 0.312.3 |
References
- https://github.com/strawberry-graphql/strawberry/security/advisories/GHSA-hv3w-m4g2-5x77
- https://nvd.nist.gov/vuln/detail/CVE-2026-35526
- https://github.com/strawberry-graphql/strawberry/commit/0977a4e6b41b7cfe3e9d8ba84a43458a2b0c54c2
- https://github.com/pypa/advisory-database/tree/main/vulns/strawberry-graphql/PYSEC-2026-134.yaml
- https://github.com/strawberry-graphql/strawberry
- https://github.com/strawberry-graphql/strawberry/releases/tag/0.312.3
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
CWE-400, CWE-770- Platform
- Python (PyPI)
- Package
strawberry-graphql- Disclosed
- 06.04.2026
- Updated
- 11.10.2026 12:19
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-134 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-hv3w-m4g2-5x77 - CC BY 4.0
Vulnerability history: strawberry-graphql
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 9
- First → latest
- 09.2024 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 3
- Medium 3
- Low 3
Disclosures per year
- 2024: 1
- 2025: 1
- 2026: 7
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strawberry-graphql: Denial of Service via unbounded WebSocket subscriptions this entry
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