CVE-2024-4989: 
WSO2 API Manager vulnerability analysis and mitigation

CVE-2024-4989 is an open redirect vulnerability in WSO2 API Manager caused by insufficient validation of the callback URL parameter, allowing unauthenticated attackers to redirect users to attacker-controlled web pages. It affects WSO2 API Manager versions 4.1.0 through 4.1.0.152, 4.2.0 through 4.2.0.104, and 4.3.0 through 4.3.0.19. The vulnerability was disclosed on October 21, 2026, and carries a CVSS v3.1 base score of 5.4 (Medium) (Github Advisory).

The root cause is improper input validation of the callback URL parameter in WSO2 API Manager's JSP layer, classified as CWE-601 (URL Redirection to Untrusted Site / Open Redirect). An unauthenticated remote attacker can craft a malicious URL containing an attacker-controlled callback destination; when a victim clicks the link, the application redirects them to the external site without validating the target. The fix was implemented via JSP improvements merged in the product's GitHub repository (Github PR, Github Advisory).

Successful exploitation enables an attacker to redirect authenticated or unauthenticated users from a trusted WSO2 API Manager URL to an arbitrary attacker-controlled web page, facilitating phishing campaigns that can harvest user credentials or other sensitive information. The confidentiality and integrity impacts are rated low, and there is no direct availability impact. Because the redirect originates from a legitimate WSO2 domain, users are more likely to trust and interact with the malicious destination, increasing the effectiveness of social engineering attacks (Github Advisory).

No public proof-of-concept exploit code has been identified, and there is no evidence of active in-the-wild exploitation at this time. The EPSS score is 0.0, indicating a very low probability of exploitation in the near term. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. No threat actor attribution has been reported (Github Advisory).

1. Reconnaissance: Identify internet-facing WSO2 API Manager instances running versions 4.1.0–4.1.0.152, 4.2.0–4.2.0.104, or 4.3.0–4.3.0.19 using tools like Shodan or Censys.
2. Craft malicious URL: Construct a URL targeting the vulnerable callback URL parameter endpoint on the WSO2 API Manager instance, embedding an attacker-controlled destination (e.g., https://apim.target.org/authz?callbackUrl=https://attacker.com/phish).
3. Distribute the link: Deliver the crafted URL to target users via email, messaging platforms, or other social engineering channels, leveraging the trusted WSO2 domain to increase credibility.
4. Victim interaction: When the victim clicks the link, the WSO2 API Manager processes the request and redirects the user's browser to the attacker-controlled page without validating the callback URL.
5. Credential harvesting: The attacker's phishing page mimics a legitimate login or consent page to capture user credentials or other sensitive information (Github Advisory).

• Network: HTTP requests to WSO2 API Manager endpoints containing a callbackUrl or similar parameter pointing to external or suspicious domains; outbound redirects (HTTP 302) from the API Manager to non-whitelisted external URLs.
• Logs: Web server or application access logs showing requests with callback URL parameters containing external domains (e.g., callbackUrl=https://[external-domain]); repeated access from the same source IP crafting varied callback URLs.
• User Reports: End-user reports of unexpected redirects from the WSO2 API Manager portal to unfamiliar or suspicious websites.

WSO2 has released patched versions addressing this vulnerability: 4.1.0.153 or later for the 4.1.x branch, 4.2.0.105 or later for the 4.2.x branch, and 4.3.0.20 or later for the 4.3.x branch. Organizations should upgrade to the appropriate patched version as the primary remediation. As additional hardening measures, implement server-side allowlist validation for callback URL parameters, deploy security headers, and educate users to recognize suspicious redirects and phishing attempts (Github Advisory, WSO2 Advisory).