CVE-2026-48710
Description
A flaw was found in Starlette, a lightweight ASGI (Asynchronous Server Gateway Interface) framework. A remote attacker could exploit this vulnerability by sending a specially crafted HTTP Host request header. This malformed header could cause the request.url to be incorrectly reconstructed, leading to a discrepancy with the actual requested path. Consequently, security restrictions enforced by middleware and endpoints that rely on request.url for validation could be bypassed, potentially allowing unauthorized access or actions.
Statement
The impact of this vulnerability is rated Moderate. A malformed Host header can manipulate the reconstructed request.url.path, introducing a discrepancy with the canonical ASGI request path (scope["path"]). However, the vulnerability does not directly grant access, modify routing, or bypass security controls on its own. A path-based authentication or authorization bypass is possible only if an application depends on request.url.path for access control decisions rather than the canonical ASGI path or standard framework mechanisms. The impact relies heavily on downstream application design rather than a default library failure.
Red Hat Satellite / Insights (IoP): The starlette package is included as a dependency of Connexion, but this flaw is rated Low impact because these services do not use path-based authentication middleware and all services are deployed behind reverse proxies.
OpenShift Lightspeed (OLS): The starlette package is included as a dependency, but this flaw is rated Low impact because authentication is enforced via Kubernetes TokenReview/SubjectAccessReview through FastAPI dependency injection, not path-based middleware; request.url.path is only used for metrics and response header application.
RHOAI Kubeflow Training images: starlette is being used as indirect dependency of mlflow, but this flaw is rated as Low impact because mlflow is used as client library only to store training metrics on remote server, it doesn't expose any endpoint.
RHOAI odh-automl: The impact is reduced to Low since starlette is only used in the backend and it's transient dependency and starlette is not used at all to serve any endpoints.
RHOAI odh-kserve-autogluon-server-rhel9: While the Starlette dependency is present in the build, the vulnerable code in starlette is not reachable. This reduces the impact to low.
Mitigation
Deploying an RFC-compliant reverse proxy (such as nginx, Apache, HAProxy, or Caddy) in front of the ASGI server will reject malformed Host headers before they reach the application. This is the most straightforward mitigation that does not require code changes.
If custom middleware is present, it should be updated to use `request.scope["path"]` instead of `request.url.path` for any security decisions. The ASGI scope path is derived from the HTTP request line and is not influenced by the Host header, so it reflects the actual request target.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.5 | 6.5 | 6.5 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | Low | Low | Low |
| Privileges Required | None | None | None |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | Low | Low | Low |
| Integrity Impact | Low | Low | Low |
| Availability Impact | None | None | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Understanding the Weakness (CWE)
Other
Technical Impact: Varies by Context
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