CVE-2026-48710

python-starlette: Missing Host header validation poisons request.url.path, bypassing path-based security checks

CVE-2026-48710 is fixed in 4 products on 1 platform, first by FEDORA-2026-E0F378428E, released May 28, 2026. It is being exploited: CISA added it to the Known Exploited Vulnerabilities catalog on September 2, 2026. Patch Radar priority: Patch now.

Patch nowCISA KEV

CVSS

6.5

medium

Exploitation

Exploited

Listed by CISA

CISA KEV

Sep 2, 2026

Federal due date Sep 16, 2026

EPSS

0.7029

99th percentile

Missing Host header validation poisons request.url.path, bypassing path-based security checks

Where it's fixed

Product	Fixed in	Fix	Released
Linux
python-starlette · Fedora 43	0.52.1-2.fc43	FEDORA-2026-E0F378428E	May 28, 2026
python-starlette · opensuse-leap 16.0	0.41.3-160000.3.1	OPENSUSE-SU-2026:20975-1	Jun 17, 2026
python-starlette · sles 16.0	0.41.3-160000.3.1	SUSE-SU-2026:22151-1	Jun 17, 2026
python3-starlette · Fedora 43	0.52.1-2.fc43	FEDORA-2026-E0F378428E	May 28, 2026
python3-starlette+full · Fedora 43	0.52.1-2.fc43	FEDORA-2026-E0F378428E	May 28, 2026
starlette · Debian 12.15 (bookworm)	0.26.1-1+deb12u1	DEBIAN-CVE-2026-48710	Jun 24, 2026
starlette · Debian 13.5 (trixie)	0.46.1-3+deb13u2	DEBIAN-CVE-2026-48710	Jun 24, 2026
starlette · Debian 14	1.1.0-1	DEBIAN-CVE-2026-48710	Jun 24, 2026

Details

Published
May 26, 2026
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
CISA 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 evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

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