CVE-2026-1527

Published: Mar 12, 2026 Last Modified: Mar 12, 2026

ExploitDB:

Other exploit source:

Google Dorks:

MEDIUM 4,6

Source: ce714d77-add3-4f53-aff5-83d477b104bb

Attack Vector: network

Attack Complexity: low

Privileges Required: low

User Interaction: required

Scope: unchanged

Confidentiality: low

Integrity: low

Availability: none

Description

AI Translation Available

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`
}