SB2026052254 - Input validation error in starlette

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Main Vulnerability Database SB2026052254

SB2026052254 - Input validation error in starlette

Published: May 22, 2026

Security Bulletin ID SB2026052254
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Input validation error (CVE-ID: N/A)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to bypass path-based security checks.

The vulnerability exists due to improper input validation in request.url reconstruction when processing a malformed Host header. A remote attacker can send a specially crafted Host header to bypass path-based security checks.

The issue occurs because routing uses the raw HTTP path while security-sensitive code may rely on request.url.path reconstructed from the Host header.


Remediation

Install update from vendor's website.

References