CVE-2026-19023 The HDF Group CVE debrief

Who should care

Users of HDF5 versions before 2.1.1 who use the h5dump tool to dump variable-length string datasets in binary mode should be aware of this vulnerability and take steps to mitigate it. This includes operators, security teams, and vulnerability management teams who need to assess the impact on their systems and plan for mitigation. Additionally, platform administrators and security engineers may need to review the per-element stride calculation in the render_bin_output function and consider implementing compensating controls to mitigate potential attacks. HDF5 users should also monitor for potential denial of service attacks and review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance. Asset owners and change managers should track exceptions, retest remediated assets, and close the item only after evidence is documented. This affects teams responsible for data integrity, system security, and compliance with security standards. They should confirm whether affected product deployments exist in managed environments and assign an owner for follow-up. Security teams should check relevant monitoring, detection, and logs for exposed assets that need extra review. They should also plan vendor-supported updates or mitigations through normal change control where exposure is confirmed. Compensating controls should be reviewed for exposed systems while remediation is scheduled and verified. This impacts teams that manage data storage, processing, and security configurations. They need to ensure that proper mitigations are in place to prevent exploitation. Teams should also be aware of potential impacts on data integrity and system availability. They should work closely with vendors and security teams to ensure that all necessary steps are taken to mitigate this vulnerability effectively. This requires coordination between development, operations, and security teams to ensure a comprehensive response. Teams should also consider implementing additional security measures such as enhanced monitoring and incident response plans to address potential threats. By taking these steps, organizations can minimize the risk associated .

Technical summary

The vulnerability is caused by an untrusted pointer dereference in the render_bin_output function in the h5dump tool in HDF5 before 2.1.1. This allows attackers to cause a denial of service via a variable-length string dataset with more than one element dumped in binary mode, which corrupts the per-element stride calculation and causes subsequent elements to be read from a misaligned offset and dereferenced as a pointer. The affected product is HDF5, and the vulnerability has a medium defensive priority. Users should verify the version of HDF5 is 2.1.1 or later and review the per-element stride calculation in the render_bin_output function.

Defensive priority

Medium

Recommended defensive actions

• Verify the version of HDF5 is 2.1.1 or later.
• Check for any variable-length string datasets with more than one element dumped in binary mode.
• Monitor for potential denial of service attacks.
• Review the per-element stride calculation in the render_bin_output function.
• Consider implementing compensating controls to mitigate potential attacks.

Evidence notes

The source item URL https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-08-05T12%3A17%3A29.000Z&lastModEndDate=2026-08-06T05%3A15%3A55.000Z provides information about the CVE-2026-19023 vulnerability. The NVD entry is currently empty. The CVE record was published on 2026-08-05T23:16:53.187Z and has not been modified since then. Users should verify the version of HDF5 is 2.1.1 or later and review the per-element stride calculation in the render_bin_output function.

Official resources