CVE-2024-21390

MFA-code theft and stored-account alteration

Published Mar 12, 2024 · Updated May 3, 2025

Improper authentication in Microsoft Authenticator before 6.2401.0617 allows local users to access MFA codes and alter stored accounts. Microsoft has not disclosed the affected authentication locus or the operation that improperly authorizes access to Authenticator data. Exploitation requires access to the victim's local device and the victim to close and reopen the app; it exposes MFA codes and permits stored accounts to be modified or deleted.

CVSS severity7.1
High
EPSS probability1.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in Microsoft Authenticator before 6.2401.0617 allows local users to access MFA codes and alter stored accounts. Microsoft has not disclosed the affected authentication locus or the operation that improperly authorizes access to Authenticator data. Exploitation requires access to the victim's local device and the victim to close and reopen the app; it exposes MFA codes and permits stored accounts to be modified or deleted.

The record

CVE
CVE-2024-21390
Published
Mar 12, 2024
Updated
May 3, 2025
Vendor
Microsoft
Product
Microsoft Authenticator
Classifications
CWE-287, T1111
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 12, 2024CVE publishedPublication date reported by the CVE source.
  2. May 3, 2025Record 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=1.0.0 <6.2401.0617

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft Authenticatorversion=1.0.0 <6.2401.0617

Published CVSS scores

7.1Microsoft CorporationCVSS:3.1/AV:L/AC:L/PR:N/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication
T1111Multi-Factor Authentication Interception

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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