CVE-2026-33975 HIGH

CVE-2026-33975: twenty-server SSRF protection bypass via IPv4-mapped IPv6 address normalization

Vendor Twentyhq
Product twenty
Weakness CWE-918 · SSRF
Published May 5, 2026
Last update May 6, 2026

CVSS base score

8.3/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N

What the vulnerability does

01Description

Twenty is an open source CRM built with NestJS (Node.js). In versions 1.18.0 and earlier, the SSRF protection in twenty-server's SecureHttpClientService can be bypassed using IPv4-mapped IPv6 addresses in URL IP literals. Node.js's URL parser normalizes IPv4-mapped IPv6 addresses to compressed hex form (e.g., ::ffff:169.254.169.254 becomes ::ffff:a9fe:a9fe), but the isPrivateIp utility only recognizes the dotted-decimal notation. As a result, the hex form passes the SSRF check unchecked. Additionally, the socket lookup validation event does not fire for IP literal addresses, bypassing the second validation layer. An authenticated user can reach any internal IP, including cloud metadata endpoints, to exfiltrate credentials such as IAM keys.

Key dates

02Disclosure timeline

May 5, 2026 CVE published
May 6, 2026 Record updated