VulnTideExploited vulnerabilities, by vendor. Data as of .
Known exploitedIn CISA's KEV catalog since Ransomware use: unknown
Kludex Starlette

CVE-2026-48710: Kludex Starlette HTTP Request/Response Smuggling Vulnerability

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 99 days after the CVE record was published.

How likely is exploitation in the next 30 days?
70.3%

EPSS score, percentile 99.4 of all scored records

How severe?
6.5 Medium

CVSS v3.1 base score, given by the CNA

What should I do?

CISA deadline . Apply mitigations in accordance with vendor instructions … Full text

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected

  • < 1.0.1

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.

What to do

Required action, set by CISA

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 for this action: .

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

Linked from CISA's catalog entry

Affected products and versions

As listed in the CVE record.

Kludex starlette
StatusVersions
Affected< 1.0.1

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.

About this vulnerability

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.

Summary: CISA's KEV catalog, as of .

  • CISA added CVE-2026-48710 to its Known Exploited Vulnerabilities (KEV) catalog on 2 Sep 2026.
  • CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
  • The due date CISA sets for the required action is 16 Sep 2026.
  • The CVE record was published on 26 May 2026, 99 days before it was added to KEV.
  • The CVE record carries a CVSS v3.1 base score of 6.5 (Medium), given by its CNA.
  • FIRST's EPSS model puts the probability of exploitation in the next 30 days at 70.3% (percentile 99.4), as of 28 Oct 2026.
  • CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact partial.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.

Description

Starlette has missing Host header validation that poisons request.url.path, bypassing path-based security checks

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.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.

Weakness

  • CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.

Timeline

DateEvent
CVE record published
Added to CISA KEV
CISA due date for the required action
CVE record last updated

References