CVE-2026-55789
CVE-2026-55789 is a high-severity vulnerability with a CVSS 3.x base score of 8.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-91.
Key facts
- Severity: High (CVSS 3.x base score 8.5)
- EPSS exploit prediction: 0% (23rd percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-91
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2026-55789?
- 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.
- How severe is CVE-2026-55789?
- CVE-2026-55789 has a CVSS 3.x base score of 8.5, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability none.
- Is CVE-2026-55789 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-55789?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2026-55789 published?
- CVE-2026-55789 was published on 2026-07-10 and last updated on 2026-07-13.
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
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