CVE-2026-48710

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. Limited direct impact.

In the wild

CISA lists this as exploited in real attacks. Treat as urgent.

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-05-22 18:47 UTC ReservedThe CVE id was reserved by its CNA
2. 2026-05-26 22:16 UTC PublishedDisclosed publicly on CVE.org and NVD
3. 2026-09-02 Exploited in the wildAdded to CISA's Known Exploited Vulnerabilities list
4. 2026-09-16 Remediation deadlineCISA's due date for federal agencies to fix it
5. 2026-10-01 18:17 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: yes, CISA lists it. This puts it above everything that is not.
• Exploit odds: 70.3% in the next 30 days (EPSS).
• Severity: 6.5 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-05-26 22:16 UTC

Last modified

2026-10-01 18:17 UTC

Added to CISA KEV

2026-09-02

Exploit probability

70.3% · EPSS, next 30 days

Weakness

CWE-444

Record status

Analyzed

Affected

• Encode Starlette < 1.0.1
• Redhat Ai Inference Server ≤ 3.3.5
• Redhat Ansible Automation Platform 2.6
• Redhat Ansible Automation Platform 2.7
• Redhat Migration Toolkit For Applications < 8.2.0
• Redhat Openshift Ai < 3.3.5
• Redhat Openshift Ai < 3.4.2
• Redhat Openshift Lightspeed

Attack profile CVSS 3.1 · 6.5

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-48710.md and follow it. Check whether this project is affected by CVE-2026-48710. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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