CVE-2026-55377
Logto MFA step-up bypass allows attacker-managed passkeys without proving possession.
Is CVE-2026-55377 being exploited?
Not confirmed. CVE-2026-55377 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.46% probability of exploitation in the next 30 days.
How severe is CVE-2026-55377?
CVE-2026-55377 is rated High with a CVSS score of 8.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-55377?
Yes. A fix has been recorded for CVE-2026-55377. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-55377 affect?
CVE-2026-55377 affects Logto < 1.41.0, Logto Account Center routes, WebAuthn registration verification records. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-55377?
Upgrade to Logto >=1.41.0; revoke exposed tokens; audit MFA changes
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authenticated actor with an Account API bearer token can bypass MFA step-up, register passkeys, manage MFA, and enable account takeover.
Immediate action required
- affected< 1.41.0
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.