Medium [CVE-2026-26199] Denial of Service via buffer underflow in H5Iget_name

HDF5 is a high-performance library and a file format specification that implements the HDF5 data model. If `H5Iget_name` is invoked on a group id with `0` for the size parameter, it will underflow when trying to place a null terminator in the buffer.

This can occur if `H5Iget_name` is invoked in a way where `size` can be forced to zero, and there is important data before the `name` buffer. A flaw was found in HDF5, a library used for managing large datasets.

This vulnerability occurs when a specific function, H5Iget_name, is called with an invalid size parameter, leading to a buffer underflow. An attacker could exploit this by providing specially crafted input, potentially causing the application to crash or become unavailable, resulting in a denial of service (DoS).

This Moderate vulnerability in HDF5 involves a buffer underflow in the `H5Iget_name` function, which can lead to a denial of service. Exploitation requires an attacker to provide specially crafted input that forces the `size` parameter to zero, a condition not commonly encountered in default Red Hat configurations, thus limiting the attack's practicality.

Red Hat severity: Moderate — CVSS 5.3 (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H). Weakness: CWE-124.

Affected Red Hat products: Red Hat AI Inference Server; Red Hat Enterprise Linux AI (RHEL AI) 3; Red Hat OpenShift AI (RHOAI).