Vulnerability Description
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.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/logto-io/logto/commit/9097054860f0d638d90778d3dcde2ba050b844b
- https://github.com/logto-io/logto/pull/9107
- https://github.com/logto-io/logto/releases/tag/v1.41.0
- https://github.com/logto-io/logto/security/advisories/GHSA-vfpw-vq44-4p63
- https://github.com/logto-io/logto/security/advisories/GHSA-vfpw-vq44-4p63
FAQ
What is CVE-2026-55789?
CVE-2026-55789 is a vulnerability with a CVSS score of 8.5 (HIGH). 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...
How severe is CVE-2026-55789?
CVE-2026-55789 has been rated HIGH with a CVSS base score of 8.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-55789?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.