CVE-2026-35523 is a high-severity (CVSS 7.5) Missing Authentication vulnerability in strawberry-graphql. A fix is available for strawberry-graphql — see the affected versions and patch details below.
Authentication bypass in strawberry-graphql via legacy graphql-ws WebSocket subprotocol
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-35523.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-35523 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
strawberry-graphqlReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Strawberry up until version 0.312.3 is vulnerable to an authentication bypass on WebSocket subscription endpoints. The legacy graphql-ws subprotocol handler does not verify that a connection_init handshake has been completed before processing start (subscription) messages. This allows a remote attacker to skip the on_ws_connect authentication hook entirely by connecting with the graphql-ws subprotocol and sending a start message directly, without ever sending connection_init.
The graphql-transport-ws subprotocol handler is not affected, as it correctly gates subscription operations on a connection_acknowledged flag. However, both subprotocols are enabled by default in all framework integrations that support websockets, and the subprotocol is selected by the client via the Sec-WebSocket-Protocol header.
Any application relying on on_ws_connect for authentication or authorization is affected.
Mitigation: Upgrade to the patched version, or explicitly disable the legacy graphql-ws subprotocol by setting subscription_protocols=[GRAPHQL_TRANSPORT_WS_PROTOCOL] on your GraphQL view/router.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | strawberry-graphql | all versions | 0.312.3pip install --upgrade 'strawberry-graphql==0.312.3' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for strawberry-graphql, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update strawberry-graphql to 0.312.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-35523 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-35523 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-35523. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-35523 in your dependencies?
O3 Security finds CVE-2026-35523 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.