CVE-2026-55789
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.40%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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 3.1
- 8.5 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:N
- EPSS
- 0.40% probability · 34th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-91
- Source
- security-advisories@github.com
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
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.