What’s Vulnerable › Vulnerabilities

CVE-2026-62317: Logto: ReDoS via unescaped user input in email subaddressing regex (blockSubaddressing)

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-19 · updated 2026-09-09
• Weakness: CWE-1333

Description

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

References

• https://github.com/logto-io/logto/commit/021381237511bc0d42f81d65df8b036b01f40547
• https://github.com/logto-io/logto/pull/9106
• https://github.com/logto-io/logto/releases/tag/v1.41.0
• https://github.com/logto-io/logto/security/advisories/GHSA-qp7j-c3q2-g739
• https://github.com/logto-io/logto/security/advisories/GHSA-qp7j-c3q2-g739

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