Improper handling of highly compressed data in undici - CVE-2026-1526
Published: April 24, 2026
Vulnerability identifier: #VU127576
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-1526
CWE-ID: CWE-409
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Node.js
Affected software:
undici
undici
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to improper handling of highly compressed data in PerMessageDeflate.decompress() when decompressing incoming WebSocket frames negotiated with the permessage-deflate extension. A remote attacker can send a specially crafted compressed WebSocket frame to cause a denial of service.
Memory exhaustion occurs in native or external memory and can cause the Node.js process to crash or become unresponsive.
How to mitigate CVE-2026-1526
Install security update from vendor's website.