Description

IBM WebSphere Application Server 9.0, and 8.5 could allow a remote attacker to bypass authentication and obtain sensitive information by sending a crafted unauthenticated request.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "6.5",
  "pubDate": "2026-09-14T20:16:39.757Z",
  "pubdate": "2026-09-14T20:16:39.757Z",
  "executiveSummary": "This vulnerability involves an authentication bypass flaw within IBM WebSphere Application Server versions 9.0 and 8.5, which permits remote, unauthenticated actors to circumvent security controls.\nBy transmitting a specifically crafted HTTP request, an unauthorized attacker can successfully bypass authentication mechanisms intended to restrict access to the application environment.\nThe primary impact of this vulnerability is the unauthorized exposure and potential exfiltration of sensitive information contained within the application server.\nThe vulnerability represents a critical security failure, as it does not require prior authentication or privileged access to trigger the bypass.\nThe risk implication is significant, as successful exploitation enables attackers to access restricted resources that should be protected by the platform's authentication framework.\nThe vulnerability highlights a deficiency in the request validation or session management logic within the affected IBM WebSphere Application Server versions.",
  "technicalDetails": "The vulnerability exists within the request handling process of IBM WebSphere Application Server versions 9.0 and 8.5. The root cause is a failure in the application server's authentication filter or request validation logic, which allows certain malformed or crafted HTTP requests to bypass the established security gates.\nIn a standard deployment, the IBM WebSphere Application Server is designed to intercept incoming requests and verify the identity of the requester against a configured security realm (such as LDAP or a local user registry). If authentication is not successfully established, the request should be blocked and a 401 Unauthorized or 403 Forbidden response returned.\nThe exploitation method involves the delivery of a crafted, unauthenticated request that tricks the server into misinterpreting the request context or bypassing the security interceptors entirely. This often occurs when the server's request parsing mechanism fails to normalize or properly validate parameters, headers, or URI paths in the way the security filter expects.\nThe attack flow proceeds as follows: First, an attacker identifies the target IBM WebSphere instance reachable over the network. Second, the attacker crafts a malicious payload, likely involving specific HTTP header manipulations, URL encoding tricks, or path traversal patterns intended to confuse the application's security middleware. Third, the crafted request is sent to the target server. Fourth, if successful, the server incorrectly validates the request as authenticated or bypasses the authentication check, allowing the server to process the request as if it originated from a legitimate, authorized user.\nThe vulnerable component is the underlying web container or authentication framework of the IBM WebSphere Application Server. By successfully bypassing the authentication layer, the attacker achieves unauthorized access to protected resources, sensitive system data, or internal administrative interfaces that should be restricted to authenticated users. This leads to the potential disclosure of sensitive configuration data, user information, or business logic processed by the application.\nThere are no requirements for administrative privileges or existing user credentials to execute this exploit, making it highly attractive for remote attackers. The vulnerability is accessible over the network, placing any public-facing or internally exposed IBM WebSphere instance at risk of exploitation."
}