CVE-2026-19024 The HDF Group CVE debrief

Who should care

Organizations using HDF5 versions before 2.1.1 should prioritize mitigation efforts to prevent potential denial-of-service attacks. This includes reviewing their current deployments, assessing the risk, and implementing necessary updates or mitigations. Security teams and vulnerability management teams should also be aware of the potential impact and review their monitoring and detection capabilities.

Technical summary

A NULL pointer dereference vulnerability exists in H5Pget_fill_value in HDF5 versions before 2.1.1. An attacker can cause a denial of service via a dataset with a version 1 or 2 fill value message that has the 'defined' flag set and a negative size field. This issue can be triggered by a crafted dataset, potentially leading to a crash or unexpected behavior in applications using the HDF5 library. The vulnerability has a HIGH CVSS score of 8.2, indicating a high level of severity. Organizations using HDF5 versions before 2.1.1 should prioritize mitigation efforts to prevent potential denial-of-service attacks.

Defensive priority

High-priority defensive actions are required due to the HIGH CVSS score of 8.2. Immediate attention is needed to mitigate potential denial-of-service attacks.

Recommended defensive actions

• Verify HDF5 version and update to 2.1.1 or later if necessary
• Perform inventory checks for affected products
• Monitor for potential denial-of-service attacks
• Implement compensating controls to mitigate potential impacts
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

Evidence is limited; verify affected scope and vendor remediation status. Perform inventory checks for HDF5 versions before 2.1.1 and monitor for potential denial-of-service attacks. The CVE record was published on 2026-08-05T23:16:53.343Z and has not been modified since then. Organizations should verify their exposure and review vendor guidance for mitigation strategies.

Official resources