Starlette: Arbitrary HTTP method dispatched to HTTPEndpoint attributes via getattr

Exploitation

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

CVSS

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

EPSS

• CVE-2026-48817: 0.21% estimated exploitation activity in the next 30 days; percentile 11.63 (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.

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 DODELETE therefore resolves an attribute like dodelete and…

Published by the source

15 Jun 2026, 20:16 UTC

Last modified by the source

10 Sep 2026, 03:50 UTC

Source last checked

26 Oct 2026, 13:46 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-x746-7m8f-x49c

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-x746-7m8f-x49c

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# Patch Next advisory brief: CVE-2026-48817

Advisory: Starlette: Arbitrary HTTP method dispatched to `HTTPEndpoint` attributes via `getattr`
IDs: CVE-2026-48817, GHSA-x746-7m8f-x49c
Record: https://patchnext.com/advisories/cve-2026-48817 (revision 2, source checked 26 Oct 2026, 13:46 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: starlette 1.1.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI starlette: affected < 1.1.0; fixed in 1.1.0

## Suggested inspection (read-only)
- `python -m pip show starlette`: 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 starlette.
- 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-x746-7m8f-x49c (OSV record GHSA-x746-7m8f-x49c lists affected ranges: PyPI starlette >=0 <1.1.0 (fixed))
- Verified: https://github.com/advisories/GHSA-x746-7m8f-x49c (GitHub-reviewed advisory GHSA-x746-7m8f-x49c lists affected ranges: PyPI starlette >=0 <1.1.0)

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