CVE-2026-4967: Remote Denial of Service in IMS via Out-of-Bounds Read

Technical summary

The vulnerability stems from insufficient bounds checking in IMS's memory access logic. When processing attacker-controlled input, the application fails to validate array or buffer boundaries before executing read operations. This permits an out-of-bounds memory access that leads to application termination or undefined behavior. The CVSS 3.1 score of 7.5 (HIGH) reflects a network-exploitable flaw with high availability impact and no confidentiality or integrity consequences.

Business impact

This vulnerability can disrupt service availability for organizations relying on IMS. Denial-of-service attacks can interrupt critical workflows, degrade user experience, and potentially trigger cascading failures in dependent systems. Organizations may face operational downtime, incident response costs, and reputational impact if services are unavailable during business-critical periods.

Affected systems

The vulnerability affects IMS installations. Specific product versions, vendors, and configurations are not detailed in available advisories. Organizations deploying IMS should verify their version against vendor security bulletins and determine exposure based on network accessibility of their IMS instances.

Exploitability

The vulnerability is highly exploitable. It requires only network access (AV:N), no authentication (PR:N), no user interaction (UI:N), and can be triggered from a single request (AC:L). An attacker with basic network connectivity can immediately craft malicious input to cause denial of service, making this a straightforward attack vector requiring minimal sophistication.

Remediation

Apply vendor-provided patches immediately upon availability. Until patching is complete, implement network-level controls to restrict access to IMS services—limit exposure to trusted networks, deploy rate limiting, and monitor for suspicious traffic patterns. Verify patch deployment across all IMS instances in your environment.

Patch guidance

Contact your IMS vendor or check their security advisory portal for available patches. Apply patches during a maintenance window to ensure service continuity. Test patches in a non-production environment first to validate compatibility with your deployment. Confirm patch installation by checking version numbers and conducting functional testing. Document the patch date and version for audit purposes.

Detection guidance

Monitor for repeated failed requests or crashes of IMS processes, particularly those triggered by unusual or malformed input. Implement network intrusion detection rules to identify suspicious traffic patterns targeting IMS ports. Log all IMS API calls and review for attempts to access invalid memory ranges or trigger error conditions. Alert on unexpected IMS service restarts or high CPU spikes during processing.

Why prioritize this

This vulnerability merits prompt patching due to its HIGH CVSS score, network-exploitable nature, and lack of authentication barriers. Denial-of-service impact directly affects business continuity. The absence of KEV listing does not reduce severity; organizations should patch based on CVSS score and exploitability metrics.

Risk score, explained

The CVSS 3.1 score of 7.5 reflects a high-severity flaw: remote attack vector (AV:N), low attack complexity (AC:L), no privilege or user interaction required (PR:N, UI:N), and high availability impact (A:H). No confidentiality or integrity loss (C:N, I:N) moderates the score slightly, but the ease of exploitation and guaranteed service disruption justify the HIGH rating.

Frequently asked questions