Vulnerability · Published Jul 10, 2026 · Assigned by GitHub_M
CVE-2026-55789Logto: SAML IdP injects user-controlled profile attributes raw into signed assertions, allowing privilege escalation at relying Service Providers
High 8.5
In plain English
A high-severity security flaw in logto from logto-io. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities).
Official 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.
Affected products (as reported)
Weakness: CWE-91, CWE-1395 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:N
References
- https://github.com/logto-io/logto/security/advisories/GHSA-vfpw-vq44-4p63 x_refsource_CONFIRM
- https://github.com/logto-io/logto/pull/9107 x_refsource_MISC
- https://github.com/logto-io/logto/commit/9097054860f0d638d90778d3dcde2ba050b844b6 x_refsource_MISC
- https://github.com/logto-io/logto/releases/tag/v1.41.0 x_refsource_MISC