GHSA-x746-7m8f-x49c
MEDIUMGHSA-x746-7m8f-x49c is a medium-severity (CVSS 5.3) CWE-470 vulnerability in starlette. O3 Security confirms whether GHSA-x746-7m8f-x49c is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Starlette: Arbitrary HTTP method dispatched to `HTTPEndpoint` attributes via `getattr`
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 GHSA-x746-7m8f-x49c.
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
GHSA-x746-7m8f-x49c 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 370,894 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
starletteReal-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
Summary
When dispatching a request, HTTPEndpoint selects the handler by lowercasing the HTTP method and looking it up as an attribute with getattr, without restricting the lookup to a known set of HTTP verbs.
When an HTTPEndpoint subclass is registered through Route(...) without an explicit methods= argument, the route does not constrain the method and every method reaches the endpoint. If a non-standard HTTP method whose lowercased name matches an attribute on the endpoint subclass reaches the endpoint, that attribute is invoked as if it were a request handler. An attacker can use this to reach methods that were never meant to be HTTP handlers, such as internal helpers, without the authorization checks applied by the intended public handler.
Details
HTTPEndpoint uses the client-supplied method name to resolve an instance attribute, without validating it against the set of HTTP verbs the endpoint supports. A method such as _DO_DELETE therefore resolves an attribute like _do_delete and invokes it. Non-standard methods are valid RFC 9110 token methods, so an endpoint must not treat the method name as a trusted attribute selector.
Impact
An application is affected when all of the following hold:
- It defines an
HTTPEndpointsubclass and registers it viaRoute(...)without an explicitmethods=argument. - The subclass defines additional methods whose names match a non-standard HTTP-method token shape and that accept a single
requestargument and return a response.
This also affects frameworks built on Starlette, like FastAPI.
Mitigation
Register HTTPEndpoint subclasses with an explicit methods= argument on the Route, listing only the HTTP verbs the endpoint supports. The route then rejects any other method with 405 Method Not Allowed before it reaches the endpoint, so non-standard methods cannot resolve an attribute.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | starlette | all versions | 1.1.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for starlette. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update starlette to 1.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-x746-7m8f-x49c 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 pinpoints whether GHSA-x746-7m8f-x49c is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-x746-7m8f-x49c. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-x746-7m8f-x49c in your dependencies?
O3 detects GHSA-x746-7m8f-x49c across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.