SB2026072180 - Input validation error in Granian

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Main Vulnerability Database SB2026072180

SB2026072180 - Input validation error in Granian

Published: July 21, 2026

Security Bulletin ID SB2026072180
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Input validation error (CVE-ID: CVE-2026-42544)

CWE-ID: CWE-20 - Improper input validation

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


The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to Granian aborts a worker process when an unauthenticated client sends a WebSocket upgrade request whose Sec-WebSocket-Protocol header contains non-ASCII bytes. The crash happens in Granian's WebSocket scope construction path, before the ASGI application is invoked. A remote attacker can pass specially crafted input to the application and perform a denial of service (DoS) attack.


Remediation

Install update from vendor's website.

References