CVE-2026-11926: IBM Verify Identity Access DOS Vulnerability

CVE-2026-11926 Overview

CVE-2026-11926 is a denial of service vulnerability in IBM Verify Identity Access. A remote attacker can trigger service disruption by sending crafted requests that the application fails to validate properly. The flaw is classified under [CWE-400] Uncontrolled Resource Consumption. Exploitation requires no authentication and no user interaction, and it can be executed over the network. Successful exploitation exhausts server resources and renders the identity access service unavailable to legitimate users.

Critical Impact

An unauthenticated remote attacker can exhaust resources on IBM Verify Identity Access deployments, disrupting authentication and access management services that depend on the product.

Affected Products

• IBM Verify Identity Access (specific affected versions listed in the vendor advisory)

Discovery Timeline

• 2026-09-15 - CVE-2026-11926 published to the National Vulnerability Database (NVD)
• 2026-09-16 - Last updated in NVD database

Technical Details for CVE-2026-11926

Vulnerability Analysis

The vulnerability resides in how IBM Verify Identity Access processes incoming request resources. The application does not sufficiently validate the size, structure, or volume of resources referenced in inbound requests. An attacker who submits requests designed to consume disproportionate server resources can force the service into a resource-exhausted state.

Because IBM Verify Identity Access functions as an identity and access management gateway, its unavailability cascades to every downstream application that relies on it for authentication and authorization decisions. The impact is limited to availability. Confidentiality and integrity are not affected.

Root Cause

The root cause is uncontrolled resource consumption [CWE-400]. The request handler accepts and processes resource references without enforcing bounds on quantity, size, or processing cost. Without validation gates, malformed or oversized requests translate directly into memory, CPU, or connection pressure on the server.

Attack Vector

The attack vector is network-based and requires no privileges or user interaction. An attacker sends crafted HTTP requests to an exposed IBM Verify Identity Access endpoint. Repeated or amplified requests degrade service performance until authentication traffic can no longer be processed. The exploitation methodology and specific request patterns are described in the IBM Support Page.

No public proof-of-concept exploit and no exploitation in the wild have been reported at the time of publication.

Detection Methods for CVE-2026-11926

Indicators of Compromise

• Unexplained spikes in CPU, memory, or thread utilization on IBM Verify Identity Access nodes.
• Elevated rates of HTTP 5xx responses or connection timeouts from the Verify Identity Access endpoints.
• Repeated inbound requests from a small set of source IP addresses containing oversized or malformed resource references.
• Sudden loss of authentication availability across dependent applications.

Detection Strategies

• Baseline normal request volume and payload size to the Verify Identity Access service, then alert on statistical deviations.
• Inspect web application firewall (WAF) and reverse proxy logs for repeated requests with abnormal resource counts or sizes.
• Correlate server resource metrics with request logs to identify the specific request patterns that precede exhaustion events.

Monitoring Recommendations

• Instrument Verify Identity Access with health probes that alert on sustained resource saturation.
• Forward web-tier and application logs into a centralized analytics platform for cross-source correlation.
• Monitor upstream network devices for traffic volume anomalies targeting Verify Identity Access endpoints.

How to Mitigate CVE-2026-11926

Immediate Actions Required

• Apply the fix documented on the IBM Support Page as soon as it is available for your deployment.
• Restrict network access to the Verify Identity Access management and authentication endpoints to trusted networks only.
• Enable rate limiting and request size limits at the reverse proxy or WAF in front of Verify Identity Access.

Patch Information

IBM has published remediation guidance on the IBM Support Page. Administrators should review the advisory to identify affected versions and the corresponding fixed builds, then schedule an upgrade window.

Workarounds

• Deploy a WAF rule that rejects requests exceeding defined size and resource-count thresholds.
• Terminate long-running or oversized connections at the load balancer before they reach the application.
• Isolate Verify Identity Access behind network segmentation so only authorized clients can reach the service.
• Increase monitoring sensitivity and reduce request timeouts to fail fast under attack conditions.

# Example NGINX front-end limits to blunt resource exhaustion
http {
    limit_req_zone $binary_remote_addr zone=viareq:10m rate=20r/s;
    client_max_body_size 1m;
    client_body_timeout 10s;
    client_header_timeout 10s;

    server {
        listen 443 ssl;
        server_name verify.example.com;

        location / {
            limit_req zone=viareq burst=40 nodelay;
            proxy_pass https://verify-backend;
        }
    }
}