CVE-2026-15617: Principal/domain lookup without case normalization

Severity: critical (CVSS 9.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-23 · updated 2026-07-27
Weakness: CWE-178

Description

Logto performs principal lookup without normalizing email and identifier strings, enabling principal collision and unauthorized account access via case- or Unicode-different identities.

Affected products

Logto: from 1.10.1 through 1.37.1

References

https://github.com/logto-io/logto/blob/ea3ede35028dfd0bbb6d7b239623ce0e7f6cdff8/packages/core/src/libraries/verification-helpers/single-sign-on-guard.ts#L23-L33

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