CVE-2026-42544

Granian: Unauthenticated DoS via WebSocket subprotocol header panic

Published May 12, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Github GHSA Github GHSA GHSA-vrg7-482j-p6f6 Granian vulnerable to unauthenticated DoS via WebSocket subprotocol header panic
History
Type Values Removed Values Added
Metrics ssvc

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

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

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
May 18, 2026, 3:09 PM
Reserved
Apr 28, 2026, 4:56 PM
Status
Deferred
Published
May 12, 2026, 10:16 PM
Modified
Oct 26, 2026, 2:10 PM