Granian is a Rust HTTP server for Python applications. From 1.2.0 to 2.7.4, 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. This vulnerability is fixed in 2.7.4.
History

Mon, 18 May 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 13 May 2026 11:00:00 +0000

Type Values Removed Values Added
First Time appeared Emmett-framework
Emmett-framework granian
Vendors & Products Emmett-framework
Emmett-framework granian

Tue, 12 May 2026 22:15:00 +0000

Type Values Removed Values Added
Description Granian is a Rust HTTP server for Python applications. From 1.2.0 to 2.7.4, 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. This vulnerability is fixed in 2.7.4.
Title Granian: Unauthenticated DoS via WebSocket subprotocol header panic
Weaknesses CWE-20
CWE-248
CWE-400
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-18T15:09:40.421Z

Reserved: 2026-04-28T16:56:50.191Z

Link: CVE-2026-42544

cve-icon Vulnrichment

Updated: 2026-05-18T15:08:08.213Z

cve-icon NVD

Status : Deferred

Published: 2026-05-12T22:16:34.467

Modified: 2026-05-18T16:16:30.937

Link: CVE-2026-42544

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-13T10:35:22Z