CVE-2026-62317: Logto-Io Logto

High severity, CVSS 7.5. EPSS: 0.7% chance of exploitation in the next 30 days.

Logto is the modern, open-source auth infrastructure for SaaS and AI apps. Prior to 1.41.0, Logto's email subaddressing blocklist in packages/core/src/libraries/sign-in-experience/email-blocklist-policy.ts used the attacker-controlled domain from email input to construct subaddressingRegex when blockSubaddressing was enabled. The permissive emailRegEx accepted multiple at signs and regular expression metacharacters, and POST /api/experience/verification/verification-code could therefore cause catastrophic backtracking in subaddressingRegex.test(email). The resulting event-loop stall could make authentication, token issuance, SSO, and the administrative console unavailable. This issue is fixed in version 1.41.0.

Affected products

• Logto-Io Logto: before 1.41.0 (fixed in 1.41.0)

Published 2026-08-19. Last modified 2026-09-09.