What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 8.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-10 · updated 2026-10-25
• Weakness: CWE-91

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

• logto-io logto: before 1.41.0

References

• https://github.com/logto-io/logto/commit/9097054860f0d638d90778d3dcde2ba050b844b6
• 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

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