CVE-2024-21632Public exploitNetwork attack vector

Account takeover via unverified email claim

Published Jan 2, 2024 · Updated Jun 17, 2025

Improper authentication in Synth omniauth-microsoft_graph before 2.0.0 allows remote attackers to take over accounts via an unverified email claim. The MicrosoftGraph strategy returned the mutable Graph email attribute in the OmniAuth auth hash without checking its domain against userPrincipalName or xms_edov. Exploitation requires a relying application to trust email as its account identifier; an attacker can assign a victim email to an attacker-controlled Microsoft account and sign in as that victim.

CVSS severity8.6
High
EPSS probability0.90%
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 Synth omniauth-microsoft_graph before 2.0.0 allows remote attackers to take over accounts via an unverified email claim. The MicrosoftGraph strategy returned the mutable Graph email attribute in the OmniAuth auth hash without checking its domain against userPrincipalName or xms_edov. Exploitation requires a relying application to trust email as its account identifier; an attacker can assign a victim email to an attacker-controlled Microsoft account and sign in as that victim.

The record

CVE
CVE-2024-21632
Published
Jan 2, 2024
Updated
Jun 17, 2025
Vendor
Synth
Product
omniauth-microsoft_graph
Classifications
CWE-287, T1078
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 2, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 17, 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=< 2.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Synth · omniauth-microsoft_graphversion=< 2.0.0

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.6GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L

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.

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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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-287Improper Authentication
T1078Valid Accounts

Public exploit references

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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