# CVE-2026-48710

## Summary

- **CVE ID:** CVE-2026-48710
- **Severity:** MEDIUM
- **CVSS Score:** 6.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N)
- **CWE:** CWE-444
- **Published:** May 26, 2026
- **Last Modified:** Sep 4, 2026

## Description

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.

## Affected Products

- Kludex — starlette (< 1.0.1)

## References

- [CNA](https://github.com/Kludex/starlette/security/advisories/GHSA-86qp-5c8j-p5mr)
- [CNA](https://github.com/Kludex/starlette/commit/764dab0dcfb9033d75442d7a359645c9f94648c6)
- [CNA](https://badhost.org)
- [CNA](https://github.com/pypa/advisory-database/tree/main/vulns/starlette/PYSEC-2026-161.yaml)
- [CNA](https://ostif.org/disclosing-the-badhost-vulnerability-in-starlette)
- [CNA](https://www.secwest.net/starlette)
- [CNA](https://www.x41-dsec.de/lab/advisories/x41-2026-002-starlette)
- [redhat-SADP](https://access.redhat.com/security/cve/CVE-2026-48710)
- [redhat-SADP](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-48710.json)
- [redhat-SADP](https://www.cve.org/CVERecord?id=CVE-2026-48710)
- [redhat-SADP](https://bugzilla.redhat.com/show_bug.cgi?id=2481742)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:24866)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:23346)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:22993)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:26226)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:22992)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:30089)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:30088)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:34456)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:34532)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:34526)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:37275)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:43038)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:44696)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:51357)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:60520)
- [CISA-ADP](https:/www.microsoft.com/en-us/security/blog/2026/08/26/when-ai-infrastructure-becomes-target-securing-gateways-control-points)
- [CISA-ADP](https://www.wiz.io/blog/ai-infrastructure-honeypot)
- [CISA-ADP](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-48710)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:63337)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 36.26%
- **EPSS Percentile:** 98.4

## Known Exploited Vulnerabilities (KEV)

- **Date Added:** Sep 2, 2026
- **Due Date:** Sep 16, 2026

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._