CVE-2026-48710
Kludex Starlette HTTP Request/Response Smuggling Vulnerability
Published May 26, 2026 · updated Oct 1, 2026 · Kludex Starlette
Starlette is a lightweight ASGI framework/toolkit. Prior to version 1.0.1, the HTTP request header was not validated before being used to reconstruct . Because the routing algorithm relies on the raw HTTP path while is rebuilt from the header, a malformed header could make differ from the path that was actually requested. Middleware and endpoints that apply security restrictions based on (rather than the raw path) could therefore be bypassed. Users should upgrade to a version greater than or equal to version 1.0.1, which validates the header against the grammar of RFC 9112 §3.2 / RFC 3986 §3.2.2 when constructing and falls back to for malformed values.
Timeline
Detection, updates, and resolution for this record.
May 26, 2026 · Catalog
Detected
Starlette is a lightweight ASGI framework/toolkit. Prior to version 1.0.1, the HTTP request header was not validated before being used to reconstruct . Because the routing algorithm relies on the raw HTTP path while is rebuilt from the header, a malformed header could make differ from the path that was actually requested. Middleware and endpoints that apply security restrictions based on (rather t
Sep 2, 2026 · CISA KEV
Known exploited
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
Sep 16, 2026 · CISA KEV
Remediation due
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
Oct 1, 2026 · Catalog
Updated
Starlette is a lightweight ASGI framework/toolkit. Prior to version 1.0.1, the HTTP request header was not validated before being used to reconstruct . Because the routing algorithm relies on the raw HTTP path while is rebuilt from the header, a malformed header could make differ from the path that was actually requested. Middleware and endpoints that apply security restrictions based on (rather t
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.
CISA due date Sep 16, 2026
Affected
- cpe encode/starletteversion unspecified
- cpe redhat/ai inference serverversion unspecified
- cpe redhat/ansible automation platform2.6
- cpe redhat/ansible automation platform2.7
- cpe redhat/migration toolkit for applicationsversion unspecified
- cpe redhat/openshift aiversion unspecified
- cpe redhat/openshift lightspeedversion unspecified
- vendor Kludex Starletteversion unspecified
Sources
- CISA KEVCVE-2026-48710
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.
cisa.gov - CVE.orgCVE-2026-48710
Official CVE identifier
cve.org - FIRST EPSSCVE-2026-48710
30-day exploitation probability 7.1%
first.org - NIST NVDCVE-2026-48710
Starlette is a lightweight ASGI framework/toolkit. Prior to version 1.0.1, the HTTP request header was not validated before being used to reconstruct . Because the routing algorithm relies on the raw HTTP path while is rebuilt from the hea
nvd.nist.gov