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CVE

CVE-2026-35526

strawberry-graphql: Denial of Service via unbounded WebSocket subscriptions
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CVE

CVE-2026-35526

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.

Package Versions Affected

Package Version
patch Availability
No items found.

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CVSS Version

Severity
Base Score
CVSS Version
Score Vector
C
H
U
7.5
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
C
H
U
0
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
C
H
U
7.5
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Related Resources

No items found.

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

Severity

7.5

CVSS Score
0
10

Basic Information

Ecosystem
Base CVSS
7.5
EPSS Probability
0.00069%
EPSS Percentile
0.21361%
Introduced Version
0,0.248.0,0.101.0,0.80.0,0.106.1,0.65.3,0.12.0
Fix Available
0.312.3

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