All vulnerabilities
CVE-2026-48710GHSA-86qp-5c8j-p5mrPYSEC-2026-161X41-2026-002

Kludex Starlette HTTP Request/Response Smuggling Vulnerability

Kludex StarlettePyPILibraries & packages
Open in ThreatlineRecord JSON
CVSS
6.5Medium
ExploitationExploited in the wildAdded to KEV 2 Sep 2026CISA KEV
Exploit odds (EPSS)7.06%Chance of exploitation activity in the next 30 days, higher than 94% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in1.0.1Fixed versionGitHub
Federal deadline16 Sep 2026Remediation due date for US federal agenciesCISA KEV
CISA required actionApply 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 evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. CISA KEV

What fixes it

  • 1.0.1starlette, pipGitHub
  • 1.0.1starlette, PyPIOSVpip install "starlette>=1.0.1"

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Timeline

  1. 26 May 2026, 21:54 UTCPublishedCVE List
  2. 2 Sep 2026Added to CISA KEVCISA KEV

Public exploit code and templates 1

  • Scanner templateStarlette - Improper Validation of Unsafe Equivalence in InputNuclei

Listed so defenders can prioritize. Threatline links to the source and does not host exploit code.

Description

Kludex Starlette contains a HTTP request/response smuggling vulnerability that could allow attackers to inject paths into the host part, prepending the actual path leading to issues such as authentication bypass when the authentication depends on the reconstructed URL’s path. This vulnerability could be chaned with CVE-2026-42271.

Text from CVE List

Affected versions 53

  • starletteaffected: < 1.0.1CVE List
  • starlette, pip<=1.0.0GitHub
  • starlette, PyPIfrom first release, fixed in 1.0.1OSV
  • starlette, PyPI0.1.0OSV
  • starlette, PyPI0.1.1OSV
  • starlette, PyPI0.1.10OSV
  • starlette, PyPI0.1.11OSV
  • starlette, PyPI0.1.12OSV
  • starlette, PyPI0.1.13OSV
  • starlette, PyPI0.1.14OSV
  • starlette, PyPI0.1.15OSV
  • starlette, PyPI0.1.16OSV
  • starlette, PyPI0.1.17OSV
  • starlette, PyPI0.1.2OSV
  • starlette, PyPI0.1.3OSV
  • starlette, PyPI0.1.4OSV
  • starlette, PyPI0.1.5OSV
  • starlette, PyPI0.1.6OSV
  • starlette, PyPI0.1.7OSV
  • starlette, PyPI0.1.8OSV
  • starlette, PyPI0.1.9OSV
  • starlette, PyPI0.10.0OSV
  • starlette, PyPI0.10.1OSV
  • starlette, PyPI0.10.2OSV
  • starlette, PyPI0.10.3OSV
  • starlette, PyPI0.10.4OSV
  • starlette, PyPI0.10.5OSV
  • starlette, PyPI0.10.6OSV
  • starlette, PyPI0.10.7OSV
  • starlette, PyPI0.11.0OSV
  • starlette, PyPI0.11.1OSV
  • starlette, PyPI0.11.2OSV
  • starlette, PyPI0.11.3OSV
  • starlette, PyPI0.11.4OSV
  • starlette, PyPI0.12.0OSV
  • starlette, PyPI0.12.0b1OSV
  • starlette, PyPI0.12.0b2OSV
  • starlette, PyPI0.12.0b3OSV
  • starlette, PyPI0.12.1OSV
  • starlette, PyPI0.12.10OSV
  • starlette, PyPI0.12.11OSV
  • starlette, PyPI0.12.12OSV
  • starlette, PyPI0.12.13OSV
  • starlette, PyPI0.12.2OSV
  • starlette, PyPI0.12.3OSV
  • starlette, PyPI0.12.4OSV
  • starlette, PyPI0.12.5OSV
  • starlette, PyPI0.12.6OSV
  • starlette, PyPI0.12.7OSV
  • starlette, PyPI0.12.8OSV
  • starlette, PyPI0.12.9OSV
  • starlette, PyPI0.13.0OSV
  • starlette, PyPI0.13.1OSV

References 29