CVE-2025-13591
Full vulnerability record from the local CVENow database.
Description
The authentication endpoint of WSO2 Identity Server fails to provide a consistent system response when a username does not exist in the system, allowing attackers to differentiate between valid and invalid usernames. This difference in responses can be leveraged to enumerate existing user accounts. Successful exploitation enables an attacker to discover valid usernames within the system, significantly increasing the risk of subsequent attacks such as brute force attacks on user credentials, social engineering attacks, and information leakage. The discovered usernames can be used to craft targeted phishing emails or other social engineering campaigns.
Severity
MEDIUM
CVSS score
5.3
(v3.1)
Vulnerability status
Awaiting Analysis
Source identifier
ed10eef1-636d-4fbe-9993-6890dfa878f8
Published
2026-10-19 17:16:59.413000
Last modified
2026-10-20 20:17:10.607000
View original CVE JSON
{
"id": "CVE-2025-13591",
"sourceIdentifier": "ed10eef1-636d-4fbe-9993-6890dfa878f8",
"published": "2026-10-19T17:16:59.413",
"lastModified": "2026-10-20T20:17:10.607",
"vulnStatus": "Awaiting Analysis",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "The authentication endpoint of WSO2 Identity Server fails to provide a consistent system response when a username does not exist in the system, allowing attackers to differentiate between valid and invalid usernames. This difference in responses can be leveraged to enumerate existing user accounts.\n\nSuccessful exploitation enables an attacker to discover valid usernames within the system, significantly increasing the risk of subsequent attacks such as brute force attacks on user credentials, social engineering attacks, and information leakage. The discovered usernames can be used to craft targeted phishing emails or other social engineering campaigns."
}
],
"affected": [
{
"source": "ed10eef1-636d-4fbe-9993-6890dfa878f8",
"affectedData": [
{
"vendor": "WSO2",
"product": "WSO2 Identity Server",
"defaultStatus": "unaffected",
"versions": [
{
"version": "0",
"lessThan": "7.0.0",
"versionType": "custom",
"status": "unknown"
},
{
"version": "7.0.0",
"lessThan": "7.0.0.134",
"versionType": "custom",
"status": "affected"
},
{
"version": "7.1.0",
"lessThan": "7.1.0.42",
"versionType": "custom",
"status": "affected"
}
]
},
{
"vendor": "WSO2",
"product": "WSO2 Carbon Abstract OTP Authenticator",
"defaultStatus": "unknown",
"packageName": "org.wso2.carbon.identity.auth.otp.commons:org.wso2.carbon.identity.auth.otp.core",
"versions": [
{
"version": "1.0.5",
"lessThan": "1.0.5.3",
"versionType": "custom",
"status": "affected"
},
{
"version": "1.0.10",
"lessThan": "1.0.10.2",
"versionType": "custom",
"status": "affected"
}
]
},
{
"vendor": "WSO2",
"product": "Email OTP Authenticator",
"defaultStatus": "unknown",
"packageName": "org.wso2.carbon.identity.local.auth.emailotp:org.wso2.carbon.identity.local.auth.emailotp",
"versions": [
{
"version": "1.0.18",
"lessThan": "1.0.18.8",
"versionType": "custom",
"status": "affected"
},
{
"version": "1.0.30",
"lessThan": "1.0.30.5",
"versionType": "custom",
"status": "affected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "ed10eef1-636d-4fbe-9993-6890dfa878f8",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
"baseScore": 5.3,
"baseSeverity": "MEDIUM",
"attackVector": "NETWORK",
"attackComplexity": "LOW",
"privilegesRequired": "NONE",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "LOW",
"integrityImpact": "NONE",
"availabilityImpact": "NONE"
},
"exploitabilityScore": 3.9,
"impactScore": 1.4
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-10-20T19:31:55.443304Z",
"id": "CVE-2025-13591",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"weaknesses": [
{
"source": "ed10eef1-636d-4fbe-9993-6890dfa878f8",
"type": "Secondary",
"description": [
{
"lang": "en",
"value": "CWE-203"
}
]
}
],
"references": [
{
"url": "https://security.docs.wso2.com/en/latest/security-announcements/security-advisories/2026/WSO2-2025-4583/",
"source": "ed10eef1-636d-4fbe-9993-6890dfa878f8"
}
]
}