CVE-2026-55370Network attack vector

MFA bypass via replayed TOTP codes

Published Jul 10, 2026 · Updated Jul 10, 2026

Authentication bypass in Logto before 1.41.0 allows remote authenticated users to replay a captured TOTP code during MFA. Existing TOTP verification uses otplib's stateless check with window = 1 but stores no accepted time-step counter, so it accepts the same successful code again within the RFC 6238 window. Exploitation requires the victim's first factor and a live TOTP value, enabling MFA completion for a separate sign-in before the code expires.

CVSS severity6.4
Medium
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Logto before 1.41.0 allows remote authenticated users to replay a captured TOTP code during MFA. Existing TOTP verification uses otplib's stateless check with window = 1 but stores no accepted time-step counter, so it accepts the same successful code again within the RFC 6238 window. Exploitation requires the victim's first factor and a live TOTP value, enabling MFA completion for a separate sign-in before the code expires.

The record

CVE
CVE-2026-55370
Published
Jul 10, 2026
Updated
Jul 10, 2026
Vendor
Logto
Product
Logto
Classifications
CWE-294, T1078
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.41.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Logto · Logtoversion=< 1.41.0

Published CVSS scores

6.4Logto GitHub Security AdvisoryCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-294Authentication Bypass by Capture-replay
T1078Valid Accounts

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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