CVE-2026-1527

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` }

CVSS v3 4.6 MEDIUM

4.6^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.1 / Impact : 2.5

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction REQUIRED

Confidentiality Impact LOW

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://cna.openjsf.org/security-advisories.html
https://github.com/nodejs/undici/security/advisories/GHSA-4992-7rv2-5pvq
https://hackerone.com/reports/3487198

Configurations

No configuration.

History

13 Mar 2026, 20:06

Type	Values Removed	Values Added
Summary		(es) ImpactoCuando una aplicación pasa entrada controlada por el usuario a la opción upgrade de client.request(), un atacante puede inyectar secuencias CRLF (\r\n) para: * Inyectar encabezados HTTP arbitrarios * Terminar la solicitud HTTP prematuramente y contrabandear datos sin procesar a servicios no HTTP (Redis, Memcached, Elasticsearch) La vulnerabilidad existe porque undici escribe el valor upgrade directamente al socket sin validar caracteres de encabezado no válidos: // lib/dispatcher/client-h1.js:1121 if (upgrade) { header += `connection: upgrade\r\nupgrade: ${upgrade}\r\n` }

12 Mar 2026, 21:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-03-12 21:16

Updated : 2026-03-13 20:06

NVD link : CVE-2026-1527

Mitre link : CVE-2026-1527

CVE.ORG link : CVE-2026-1527

JSON object : View

Products Affected

No product.

CWE

CWE-93

Improper Neutralization of CRLF Sequences ('CRLF Injection')

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