CVE-2026-0637: 
WSO2 API Manager vulnerability analysis and mitigation

CVE-2026-0637 is a sensitive information disclosure vulnerability affecting multiple WSO2 products, classified as an insertion of sensitive information into log files (CWE-532). When an Event Publisher output adapter is configured with irrelevant properties, the affected products log those properties without sufficient validation or sanitization, potentially exposing user credentials or other confidential data to anyone with access to the wso2carbon log files. The vulnerability was published on August 6, 2026, and has a CVSS v3.1 base score of 4.4 (Medium) (GitHub Advisory, WSO2 Advisory). Affected products include WSO2 API Manager (versions 3.1.0–4.6.0), WSO2 Identity Server (versions 5.10.0–7.2.0), WSO2 Identity Server as Key Manager (5.10.0), WSO2 Open Banking IAM and AM (2.0.0), WSO2 API Control Plane (4.5.0–4.6.0), WSO2 Traffic Manager (4.5.0–4.6.0), WSO2 Universal Gateway (4.5.0–4.6.0), and the underlying org.wso2.carbon.event.publisher.core component across numerous versions (GitHub Advisory).

The root cause is CWE-532 (Insertion of Sensitive Information into Log File): when an Event Publisher output adapter is misconfigured with properties that are irrelevant to the adapter type, the WSO2 Carbon Event Publisher Core component logs those property values verbatim without sanitization or masking. This means that if a property such as a password or API key is inadvertently included in the adapter configuration, it will appear in plaintext in the wso2carbon log files. Exploitation requires local access to the server's log files and high privileges (e.g., system administrator or log reader role), making the attack vector local with low complexity (GitHub Advisory, WSO2 Advisory). No public proof-of-concept or technical write-up beyond the vendor advisory is currently available.

Successful exploitation allows a local attacker with high privileges and read access to wso2carbon log files to retrieve sensitive information — including user credentials, API keys, or other confidential configuration data — that was inadvertently written to logs due to Event Publisher misconfiguration. The impact is limited to confidentiality (no integrity or availability impact), and exploitation does not cross security scope boundaries. However, exposed credentials could enable subsequent unauthorized access to downstream systems or lateral movement within the environment (GitHub Advisory, WSO2 Advisory).

There is no evidence of public proof-of-concept exploit code or active in-the-wild exploitation as of the time of publication (GitHub Advisory). The NVD SSVC assessment confirms exploitation is currently "none" and the vulnerability is not automatable. The EPSS score is approximately 0.113% (2nd percentile), indicating a low probability of exploitation in the near term. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. No threat actor attribution has been reported.

1. Gain privileged local access: Obtain high-privilege access to the WSO2 server (e.g., as a system administrator or a user with read access to the WSO2 installation directory).
2. Identify misconfigured Event Publisher adapters: Review the WSO2 management console or configuration files to locate Event Publisher output adapters that have been configured with irrelevant or extraneous properties (e.g., a password field added to an adapter type that does not use it).
3. Locate the wso2carbon log files: Navigate to the WSO2 log directory (typically <WSO2_HOME>/repository/logs/) and identify the wso2carbon.log or rotated log files.
4. Search for sensitive data in logs: Use text search tools (e.g., grep -i 'password\|credential\|secret\|key') to locate plaintext sensitive values that were logged when the misconfigured adapter properties were processed.
5. Extract and leverage credentials: Use any discovered credentials or tokens to attempt unauthorized access to WSO2 services, connected APIs, or other integrated systems (GitHub Advisory, WSO2 Advisory).

• File System: Unexpected or unauthorized access to <WSO2_HOME>/repository/logs/wso2carbon.log or rotated log archives; presence of sensitive strings (passwords, tokens, API keys) in plaintext within log files.
• Logs: Log entries from the org.wso2.carbon.event.publisher.core component containing property names and values from misconfigured Event Publisher output adapters; audit log entries showing log file access by non-administrative accounts.
• Configuration: Event Publisher output adapter configurations containing properties not applicable to the selected adapter type (e.g., credential fields in adapters that do not require authentication).

WSO2 has released patched versions for all affected products. Organizations should upgrade to the following minimum versions: WSO2 API Manager (3.1.0.357, 3.2.0.465, 3.2.1.84, 4.1.0.249, 4.2.0.189, 4.3.0.100, 4.4.0.64, 4.5.0.49, 4.6.0.13), WSO2 Identity Server (5.10.0.386, 5.11.0.433, 6.0.0.260, 6.1.0.261, 7.0.0.139, 7.1.0.47, 7.2.0.8), WSO2 Identity Server as Key Manager (5.10.0.377), WSO2 Open Banking IAM (2.0.0.426), WSO2 Open Banking AM (2.0.0.406), WSO2 API Control Plane (4.5.0.50, 4.6.0.14), WSO2 Traffic Manager (4.5.0.48, 4.6.0.13), and WSO2 Universal Gateway (4.5.0.49, 4.6.0.13) (WSO2 Advisory). As interim workarounds, restrict read access to wso2carbon log files to authorized personnel only, audit and correct any Event Publisher output adapter configurations that include irrelevant properties, and review existing logs for inadvertently logged sensitive data.