Username enumeration via account-lock response discrepancy
Published May 11, 2026 · Updated May 11, 2026
Username enumeration in the Email OTP flow in affected WSO2 products allows remote attackers to identify registered accounts. During initiateAuthenticationRequest, the authenticator checks account-lock state for an attacker-supplied username and produces behavior that differs when the account exists. No authentication or user interaction is required; disclosure is limited to account existence, which supports targeted password and social-engineering attacks.
Summary
What happened
Username enumeration in the Email OTP flow in affected WSO2 products allows remote attackers to identify registered accounts. During initiateAuthenticationRequest, the authenticator checks account-lock state for an attacker-supplied username and produces behavior that differs when the account exists. No authentication or user interaction is required; disclosure is limited to account existence, which supports targeted password and social-engineering attacks.
The record
- CVE
- CVE-2024-0391
- Published
- May 11, 2026
- Updated
- May 11, 2026
- Vendor
- WSO2
- Product
- WSO2 Identity Server EmailOTP Authenticator
- Classifications
- CWE-204, CAPEC-249, T1589.003
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 11, 2026CVE publishedPublication date reported by the CVE source.
- May 11, 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.
- Affected versionversion=3.0.24 <3.0.24.6
- Affected versionversion=3.0.26 <3.0.26.16
- Affected versionversion=3.0.5 <3.0.5.8
- Affected versionversion=4.1.0 <4.1.0.8
- Affected versionversion=4.1.4 <4.1.4.9
What conditions does exploitation require?
What is affected?
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.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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