Vulnerability · Published Aug 19, 2026 · Assigned by GitHub_M

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

High 7.5

In plain English

A high-severity regular-expression denial of service in logto from logto-io. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 55% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.7%top 45.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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 (as reported)

Vendor	Product	Versions
logto-io	logto	< 1.41.0

Weakness: CWE-1333 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

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