CVE-2026-55789 HIGH

CVE-2026-55789: Logto: SAML IdP injects user-controlled profile attributes raw into signed assertions, allowing privilege escalation at relying Service Providers

Vendor Logto-Io
Product logto
Weakness CWE-91 · XML injection
Published July 10, 2026
Last update July 10, 2026

CVSS base score

8.5/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality Low
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:N

What the vulnerability does

01Description

Logto is the modern, open-source auth infrastructure for SaaS and AI apps. Prior to 1.41.0, Logto's self-hosted SAML application IdP built the signed SAML response and assertion by string-substituting user-controlled profile attributes such as name, email, and custom attribute-mapping values into element-text placeholders of a SAML XML template using samlify 2.10.0, which left those placeholders unescaped. An authenticated low-privilege user could place XML markup in a profile attribute so Logto signed a forged SAML attribute, such as an arbitrary role, allowing privilege escalation at relying Service Providers that authorize on SAML attributes. This issue is fixed in version 1.41.0.

Key dates

02Disclosure timeline

July 10, 2026 CVE published