---
cve: "CVE-2026-48710"
severity: "MEDIUM"
cvss: 6.5
epss: "1.9%"
vendor: "Kludex"
kev: false
exploited: false
published: "2026-05-26 22:16:44"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-06T00:26:17+02:00"
---

# CVE-2026-48710

> 6.5 MEDIUM · 🧪 PoC

## Beschreibung

Starlette is a lightweight ASGI framework/toolkit. Prior to version 1.0.1, the HTTP `Host` request header was not validated before being used to reconstruct `request.url`. Because the routing algorithm relies on the raw HTTP path while `request.url` is rebuilt from the `Host` header, a malformed header could make `request.url.path` differ from the path that was actually requested. Middleware and endpoints that apply security restrictions based on `request.url` (rather than the raw `scope` path) could therefore be bypassed. Users should upgrade to a version greater than or equal to version 1.0.1, which validates the `Host` header against the grammar of RFC 9112 §3.2 / RFC 3986 §3.2.2 when constructing `request.url` and falls back to `scope["server"]` for malformed values.

## CVSS-Vektor

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

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Gering | warn |
| I Integrität | Gering | warn |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- 764dab0dcfb9033d75442d7a359645c9f94648c6 (Commit)

## Referenzen

- <https://github.com/Kludex/starlette/security/advisories/GHSA-86qp-5c8j-p5mr>
- <https://github.com/Kludex/starlette/commit/764dab0dcfb9033d75442d7a359645c9f94648c6>
- <https://badhost.org>
- <https://github.com/pypa/advisory-database/tree/main/vulns/starlette/PYSEC-2026-161.yaml>
- <https://ostif.org/disclosing-the-badhost-vulnerability-in-starlette>
- <https://www.secwest.net/starlette>
- <https://www.x41-dsec.de/lab/advisories/x41-2026-002-starlette>
- <https://access.redhat.com/errata/RHSA-2026:22992>
- <https://access.redhat.com/errata/RHSA-2026:22993>
- <https://access.redhat.com/errata/RHSA-2026:23346>
- <https://access.redhat.com/errata/RHSA-2026:24866>
- <https://access.redhat.com/errata/RHSA-2026:26226>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-48710) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_