CVE-2026-33975

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

HIGH
8.3
CVSS Score
Published: May 5, 2026 at 07:19 PM UTC
Updated: July 24, 2026 at 10:20 PM UTC
1 product affected across 1 vendorTwenty

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Severity
HIGH8.3
Exploit prediction
EPSS 0.2%
SSVC
PoC

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (1)

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.3HIGHGitHub_M
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-918

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