CVE-2026-33975CWE-918

twenty-server SSRF protection bypass via IPv4-mapped IPv6 address normalization

High · published May 5, 2026

CVSS v4.0
8.3
EPSS
0%
Percentile
30.0
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
8.3 · HIGH
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
EPSS
0.00372 · 30.0th percentile
Weakness
CWE-918 · Server-Side Request Forgery (SSRF)
Published
2026-05-05T19:19Z
EPSS history
Timeline
  • 05 MAY 19:19Z
    twenty-server SSRF protection bypass via IPv4-mapped IPv6 address normalization
    cvelistv5