CVE-2026-15611VulnerabilityPublished 23 Jul 2026

VU#492466: Logto Identity Platform has authentication and authorization failures in core protocol handling

Source CERT/CC

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Mentioned vulnerabilities

Not known to be exploited.

Data as of 2 Nov 2026, 22:58 UTC

Severity

Critical

Rated by Threat Radar · No CVSS score from NVD or the CNA

EPSS: 0.4% chance of exploitation in 30 days – higher than 41% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation evidence

Disclosed: evidence found.
Public on cve.org; its publication date is not in this record
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

could not be reached for coordination. Until a patch is released, administrators should reduce the attack surface by avoiding provisioning local accounts with emails used for federated sign-in, disabling or avoiding Logto's social SAML connector, requiring MFA at the upstream identity provider for all federated sign-ins, enforcing strict domain normalization at the IdP or provisioning layer, shortening session lifetimes, aggressively invalidating sessions, monitoring authentication logs for anomalies, and placing Logto behind an identity-aware reverse proxy.

Description

The Logto Identity Platform contains multiple vulnerabilities in its authentication and single sign-on (SSO) components that weaken core identity protections. These flaws allow attackers to bypass account-ownership checks, skip multi-factor authentication (MFA), replay federated sessions, and submit identity assertions without proper validation. The issues affect OIDC, OAuth 2.1, and SAML protocols and create several paths for unauthorized access in both local and federated sign-in flows. No vendor patch or statement is currently available, and mitigation relies on defensive configurations and operational controls.

Impact

The vulnerabilities reduce the reliability of authentication and authorization decisions in Logto, allowing attackers to bypass account-ownership verification, skip local MFA requirements, replay federated SSO assertions, and inject unvalidated or unsigned identity assertions. This can lead to unauthorized access to user accounts and services protected by Logto's identity platform. The issues affect both local and federated sign-in flows and compromise core security guarantees of OIDC, OAuth 2.1, and SAML protocols within the platform.

Summary

Logto, an identity and access management system by Silverhand Inc., has multiple authentication and authorization vulnerabilities affecting its core protocol handling. Key issues include unverified email-based SSO account linking (CVE-2026-15611), nonce validation bypass when the nonce claim is omitted in id_tokens (CVE-2026-15612), non-atomic handling of IdP-initiated SAML sessions allowing replay (CVE-2026-15614), bypass of SAML Conditions element time-window checks when the element is missing (CVE-2026-15615), MFA bypass on SSO sign-ins when federated identity is verified (CVE-2026-15616), and strict but unnormalized identity attribute comparisons causing incorrect account linking (CVE-2026-15617). These vulnerabilities collectively undermine authentication reliability and authorization decisions across OIDC, OAuth 2.1, and SAML protocols, enabling unauthorized access through multiple attack vectors. Silverhand Inc.

References

kb.cert.org/vuls/id/492466 (opens in a new tab)

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