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Known exploited vulnerability

CVE-2026-48710

mediumCVSS 3.1 6.5In CISA KEVEPSS 70%Published · Kludex

The short answer

CVE-2026-48710 affects Kludex starlette and is rated medium (CVSS 6.5). CISA added it to the Known Exploited Vulnerabilities catalog on 2026-09-02: attackers are using it, so patch it first. Fixed versions are published for starlette (1.0.1).

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.

Weakness: CWE-444, CWE-1289.

Severity

6.5 medium

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

Exploited (CISA KEV)

Yes, since Sep 2, 2026

Federal due date Sep 16, 2026

EPSS, next 30 days

70%

Higher than 99% of scored CVEs

How it can be exploited

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
Low
Availability impact
None

What CISA says to do

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for…

Affected packages and fixed versions

PackageEcosystemFixed inAdvisory
starlettePyPI1.0.1GHSA-86qp-5c8j-p5mr

Is it in your code? Drop your lockfile into the free vulnerability check, or let vulnerability watch check your repository every day and open the upgrade as a pull request.

Affected products

starlette, Red Hat AI Inference Server 3.3, Red Hat Ansible Automation Platform 2.6, Red Hat Ansible Automation Platform 2.7, Red Hat Migration Toolkit for Applications 8.2, Red Hat OpenShift AI 3.3, Red Hat OpenShift AI 3.4, Red Hat Satellite 6.17, Red Hat Satellite 6.18, Red Hat Satellite 6.19, Exploit Intelligence, OpenShift Lightspeed. NVD's record lists the exact affected versions.

References

Questions

Is CVE-2026-48710 being exploited?

Yes. CISA added CVE-2026-48710 to its Known Exploited Vulnerabilities catalog on 2026-09-02, with a federal remediation due date of 2026-09-16.

How do I fix CVE-2026-48710?

Upgrade to a fixed version: starlette (PyPI) 1.0.1. CISA's required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for…

From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.

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