CVE-2026-1527

Published Mar 12, 2026

Last updated 2 months ago

Overview

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` }
Source
ce714d77-add3-4f53-aff5-83d477b104bb
NVD status
Analyzed
Products
undici

Risk scores

CVSS 3.1

Type
Secondary
Base score
4.6
Impact score
2.5
Exploitability score
2.1
Vector string
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
Severity
MEDIUM

Weaknesses

ce714d77-add3-4f53-aff5-83d477b104bb
CWE-93

Social media

Hype score
Not currently trending

Configurations