CVE-2026-15611: critical vulnerability in Logto
Unverified email-based SSO account linking
Published · Updated
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
28Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 9.1epss 0.5%
Logto allows unverified email-based SSO account linking, enabling an attacker to register an identity at a permissive IdP using a victim’s email and gain unauthorized access to the victim’s account.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Affected products
Logto · LogtoRelated CVEs — Logto
In the same product, most dangerous first.
CVE-2026-15616CRITICALLocal MFA not enforced during SSO sign-inEPSS 0.5%CVE-2026-15617CRITICALPrincipal/domain lookup without case normalizationEPSS 0.4%CVE-2026-15614HIGHIdP-initiated SAML sessions not reliably invalidated (replay)EPSS 0.3%CVE-2026-15612CRITICALLOIDC nonce validation bypassEPSS 0.2%CVE-2026-15615HIGHSAML <Conditions> element not validatedEPSS 0.2%
References
https://github.com/logto-io/logto/blob/ea3ede35028dfd0bbb6d7b239623ce0e7f6cdff8/packages/core/src/libraries/verification-helpers/single-sign-on.ts#L274https://github.com/logto-io/logto/blob/ea3ede35028dfd0bbb6d7b239623ce0e7f6cdff8/packages/core/src/routes/experience/classes/verifications/enterprise-sso-verification.ts#L284-L297