strawberry-graphql: Denial of Service via unbounded WebSocket subscriptions

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-35526: 0.27% estimated exploitation activity in the next 30 days; percentile 19.91 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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 connectioninit, 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.

Published by the source

6 Apr 2026, 18:00 UTC

Last modified by the source

8 Jun 2026, 20:00 UTC

Source last checked

26 Oct 2026, 13:44 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-hv3w-m4g2-5x77

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-hv3w-m4g2-5x77

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# Patch Next advisory brief: CVE-2026-35526

Advisory: strawberry-graphql: Denial of Service via unbounded WebSocket subscriptions
IDs: CVE-2026-35526, GHSA-hv3w-m4g2-5x77
Record: https://patchnext.com/advisories/cve-2026-35526 (revision 2, source checked 26 Oct 2026, 13:44 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: strawberry-graphql 0.312.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI strawberry-graphql: affected <= 0.312.2; fixed in 0.312.3

## Suggested inspection (read-only)
- `python -m pip show strawberry-graphql`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on strawberry-graphql.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-hv3w-m4g2-5x77 (OSV record GHSA-hv3w-m4g2-5x77 lists affected ranges: PyPI strawberry-graphql >=0 <0.312.3 (fixed))
- Verified: https://github.com/advisories/GHSA-hv3w-m4g2-5x77 (GitHub-reviewed advisory GHSA-hv3w-m4g2-5x77 lists affected ranges: PyPI strawberry-graphql >=0 <=0.312.2)

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