CVE-2026-1527

CVE Details

Release Date:	2026-03-12
Impact:	Moderate	What is this?

Description

ImpactWhen an application passes user-controlled input to the upgrade option of client.request(), an attacker can inject CRLF sequences (\r\n) to: * Inject arbitrary HTTP headers * Terminate the HTTP request prematurely and smuggle raw data to non-HTTP services (Redis, Memcached, Elasticsearch) The vulnerability exists because undici writes the upgrade value directly to the socket without validating for invalid header characters: // lib/dispatcher/client-h1.js:1121 if (upgrade) { header += `connection: upgrade\r\nupgrade: ${upgrade}\r\n` }

See more information about CVE-2026-1527 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	6.5
Vector String:	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L
Version:	3.1
Attack Vector:	Network
Attack Complexity:	Low
Privileges Required:	Low
User Interaction:	Required
Scope:	Changed
Confidentiality Impact:	Low
Integrity Impact:	Low
Availability Impact:	Low

Errata information

Platform	Errata	Release Date
Oracle Linux version 9 (nodejs)	ELSA-2026-7350	2026-04-10
Oracle Linux version 9 (nodejs-nodemon)	ELSA-2026-7350	2026-04-10
Oracle Linux version 9 (nodejs-packaging)	ELSA-2026-7350	2026-04-10