Evidence used
- No CISA KEV confirmation is currently recorded.
- The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
- EPSS is 0.24% for the current model date.
BlackTreeCVE IntelligenceWSO2 · WSO2 API Manager
Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.
Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.
Patch availableWhen a WSO2 product is configured to use an external user store, the system fails to adequately obscure the existence or validity of usernames during authentication attempts. This oversight allows an attacker to repeatedly query the authentication mechanism with different username guesses, enabling the enumeration of valid usernames present in the external user store. The discovery of valid usernames can increase the risk of targeted brute-force attacks, social engineering, and information leakage. Attackers can leverage this information to craft more convincing phishing campaigns or other social engineering tactics to trick users into revealing sensitive data. The presence of username enumeration could also negatively impact an organization's reputation, leading to loss of customer trust, regulatory non-compliance, and potential legal and financial repercussions.
When a WSO2 product is configured to use an external user store, the system fails to adequately obscure the existence or validity of usernames during authentication attempts. This oversight allows an attacker to repeatedly query the authentication mechanism with different username guesses, enabling the enumeration of valid usernames present in the external user store. The discovery of valid usernames can increase the risk of targeted brute-force attacks, social engineering, and information leakage. Attackers can leverage this information to craft more convincing phishing campaigns or other social engineering tactics to trick users into revealing sensitive data. The presence of username enumeration could also negatively impact an organization's reputation, leading to loss of customer trust, regulatory non-compliance, and potential legal and financial repercussions.
The product provides different responses to incoming requests in a way that reveals internal state information to an unauthorized actor outside of the intended control sphere.
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
When a WSO2 product is configured to use an external user store, the system fails to adequately obscure the existence or validity of usernames during authentication attempts. This oversight allows an attacker to repeatedly query the authentication mechanism with different username guesses, enabling the enumeration of valid usernames present in the external user store. The discovery of valid usernames can increase the risk of targeted brute-force attacks, social engineering, and information leakage. Attackers can leverage this information to craft more convincing phishing campaigns or other social engineering tactics to trick users into revealing sensitive data. The presence of username enumeration could also negatively impact an organization's reputation, leading to loss of customer trust, regulatory non-compliance, and potential legal and financial repercussions.
The product provides different responses to incoming requests in a way that reveals internal state information to an unauthorized actor outside of the intended control sphere.
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
CWE-204: Observable Response Discrepancy. The product provides different responses to incoming requests in a way that reveals internal state information to an unauthorized actor outside of the intended control sphere.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:NCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
Operational remediation based on structured source evidence.
Published 21 Oct 2026 · Last source change 21 Oct 2026, 13:49 UTC · CWE-204 · Observable Response Discrepancy
Core structured fields are present and their contributing authorities are shown above.