CVE-2026-48817

Starlette: Arbitrary HTTP method dispatched to `HTTPEndpoint` attributes via `getattr`

Published Jun 17, 2026 CVSS 3.1 · 5.3 Medium EPSS < 1% KEV · Not listed
Description
Starlette is a lightweight ASGI framework/toolkit. In versions 1.0.1 and below, 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. An application (including Starlette-based frameworks like FastAPI) is affected if it registers an HTTPEndpoint subclass via Route(...) without explicitly setting methods=, and that subclass includes extra methods named like non-standard HTTP verbs that take one request argument and return a response. This issue has been fixed in version 1.1.0.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4711-1 starlette security update
Debian DSA Debian DSA DSA-6478-1 starlette security update
Github GHSA Github GHSA GHSA-x746-7m8f-x49c Starlette: Arbitrary HTTP method dispatched to `HTTPEndpoint` attributes via `getattr`
History
Type Values Removed Values Added
First Time appeared Kludex
Kludex starlette
Vendors & Products Kludex
Kludex starlette
Type Values Removed Values Added
Weaknesses CWE-749
References
Metrics threat_severity

None

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

threat_severity

Moderate

Type Values Removed Values Added
Description Starlette is a lightweight ASGI framework/toolkit. In versions 1.0.1 and below, 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. An application (including Starlette-based frameworks like FastAPI) is affected if it registers an HTTPEndpoint subclass via Route(...) without explicitly setting methods=, and that subclass includes extra methods named like non-standard HTTP verbs that take one request argument and return a response. This issue has been fixed in version 1.1.0.
Title Starlette: Arbitrary HTTP method dispatched to `HTTPEndpoint` attributes via `getattr`
Weaknesses CWE-470
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Jun 18, 2026, 1:54 PM
Reserved
May 22, 2026, 8:57 PM
Status
Analyzed
Published
Jun 17, 2026, 8:17 PM
Modified
Oct 25, 2026, 11:10 PM
Severity
Moderate
Public date
Jun 17, 2026, 7:48 PM