CVE-2026-21714: A memory leak occurs in Node.js HTTP/2 servers when a client sends WINDOW_UPDATE frames on stream 0 (connection-level) that cause the flow control window to exceed the maximum value of 2³¹-1. The server correctly sends a GOAWAY frame, but the Http2Session object is never cleaned up. This vulnerability affects HTTP2 users on Node.js 20, 22, 24 and 25.

Overview

Severity

Medium (CVSS 5.3)

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Exploit Status

Not Exploited

Patch Tuesday

2026-Mar

Released

2026-04-01

Last Updated

2026-04-09

EPSS Score

0.45% (percentile: 36.1%)

Affected Products (2)

Open Source Software

• azl3 nodejs24 24.13.0-3 on Azure Linux 3.0

Other

• 21111-17084

Revision History

• 2026-04-01: Information published.
• 2026-04-08: Information published.
• 2026-04-09: Information published.