CVE-2026-11928: IBM Verify Identity Access Buffer Overflow

CVE-2026-11928 Overview

CVE-2026-11928 is a buffer overflow vulnerability in IBM Verify Identity Access, an enterprise identity and access management platform. The flaw is classified under [CWE-787] Out-of-Bounds Write, indicating that untrusted input can cause the application to write data beyond the boundaries of an allocated memory buffer. The vulnerability is exploitable over the network without authentication or user interaction, and can compromise the confidentiality, integrity, and availability of the affected system. IBM has published a support advisory addressing the issue.

Critical Impact
Unauthenticated remote attackers can trigger an out-of-bounds write in IBM Verify Identity Access, potentially leading to arbitrary code execution or denial of service on identity infrastructure.

Affected Products

IBM Verify Identity Access (refer to the IBM Support Page for affected version ranges)

Discovery Timeline

2026-09-15 - CVE-2026-11928 published to NVD
2026-09-17 - Last updated in NVD database

Technical Details for CVE-2026-11928

Vulnerability Analysis

CVE-2026-11928 is an out-of-bounds write condition [CWE-787] in IBM Verify Identity Access. The product handles authentication, single sign-on, and access enforcement for enterprise applications, making it a high-value target on the network perimeter. An attacker who can reach an exposed service can send crafted input that overflows a fixed-size buffer, corrupting adjacent memory.

Successful exploitation can overwrite control data such as return addresses, function pointers, or heap metadata. Depending on the memory layout and mitigations in place, the outcome ranges from process termination to arbitrary code execution in the context of the vulnerable service. Because IBM Verify Identity Access brokers authentication decisions, code execution in this component undermines trust across every downstream application it protects.

Root Cause

The root cause is insufficient bounds checking on input processed by the affected component. The service copies attacker-controlled data into a buffer without validating that the input length fits the destination. IBM has not published detailed technical internals; refer to the IBM Support Page for advisory content and fixed versions.

Attack Vector

The attack vector is network-based and does not require authentication or user interaction. An attacker sends a malformed request to an exposed IBM Verify Identity Access endpoint. The request contains an oversized or malformed field that triggers the out-of-bounds write during parsing. No verified proof-of-concept exploit is publicly available at this time, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.

// No verified public proof-of-concept is available.
// Refer to the IBM advisory for technical detail:
// https://www.ibm.com/support/pages/node/7286188

Detection Methods for CVE-2026-11928

Indicators of Compromise

Unexpected crashes, restarts, or core dumps of IBM Verify Identity Access processes, particularly correlated with inbound requests from external sources.
Abnormally large or malformed request payloads directed at Verify Identity Access authentication or administration endpoints.
New or unexpected child processes spawned by the Verify Identity Access service account.
Outbound connections from the Verify Identity Access host to untrusted destinations following an anomalous inbound request.

Detection Strategies

Inspect web application firewall and reverse proxy logs for requests with oversized headers, parameters, or body fields targeting Verify Identity Access endpoints.
Correlate service crash events with preceding network requests to identify probable exploitation attempts.
Baseline normal request sizes and content types to Verify Identity Access, then alert on statistical outliers.

Monitoring Recommendations

Forward Verify Identity Access application, system, and audit logs to a centralized SIEM for retention and correlation.
Monitor process integrity on the host running Verify Identity Access, including unexpected memory allocations and module loads.
Track authentication anomalies downstream of Verify Identity Access, such as sudden bypass of policy enforcement or unusual token issuance patterns.

How to Mitigate CVE-2026-11928

Immediate Actions Required

Apply the fixed version listed on the IBM Support Page as soon as change control allows.
Restrict network exposure of Verify Identity Access management and authentication endpoints to trusted networks only.
Place the service behind a hardened reverse proxy or web application firewall configured to enforce strict request size limits.
Review recent logs for signs of exploitation attempts and initiate incident response if crashes coincide with suspicious traffic.

Patch Information

IBM has published remediation guidance on the IBM Support Page. Administrators should identify their installed version, cross-reference it against the affected version table in the advisory, and upgrade to the fixed release. No workaround substitutes for applying the vendor patch.

Workarounds

Limit inbound access to Verify Identity Access to known administrative and application source addresses using network segmentation and firewall rules.
Enforce request-size and content-type restrictions at an upstream WAF or load balancer to reduce the attack surface until patching is complete.
Disable or firewall off any non-essential Verify Identity Access services and interfaces.

bash

# Example: restrict inbound access to Verify Identity Access endpoints
# Replace addresses with your trusted management and application subnets
iptables -A INPUT -p tcp --dport 443 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP