OESA-2026-3262

HDF5 is a data model, library, and file format for storing and managing data. It supports an unlimited variety of datatypes, and is designed for flexible and efficient I/O and for high volume and complex data. HDF5 is portable and is extensible, allowing applications to evolve in their use of HDF5. The HDF5 Technology suite includes tools and applications for managing, manipulating, viewing, and analyzing data in the HDF5 format.

Security Fix(es):

Heap-based buffer overflow in the SOHM list-index deserialization code in HDF5 through 2.1.1 on all platforms allows attackers to cause a denial of service (crash) via a crafted HDF5 file whose shared-message list index declares a nummessages count exceeding listmax, triggering out-of-bounds heap reads and writes in H5SMcachelistdeserialize and H5SMcachelistverify_chksum.(CVE-2026-17572)

A double free vulnerability was discovered in the HDF5 library. Processing a crafted HDF5 file containing an oversized chunk size field via h5repack may cause the application to abort due to a double free.(CVE-2026-17573)

HDF5 contains a NULL pointer dereference vulnerability. Processing a crafted HDF5 file containing an attribute with an invalid variable-length datatype type field may cause the application to crash when the attribute is read.(CVE-2026-17574)

HDF5 is a high-performance library and a file format specification that implements the HDF5 data model. If a file is corrupted such that an array datatype's size, the number of elements, and the element size are not in agreement it can trigger an out of bounds read. The array datatype stores the full size of the datatype (dt->shared->size) separately from the number of elements (dt->shared->u.array.nelem) and the element size (dt->shared->parent->shared->size). If any one of these are corrupted so that they don't align with the others (element size * nelem = full size), it can lead to an out of bounds read. Depending on what is corrupted, it can alter the type of out of bounds read triggered. The vulnerability is present only in files that have been maliciously altered, as its generally not possible to independently alter the full size of the datatype, the element count and the element size. As such, this is only present if a malicious actor is altering files, and won't appear in regular usage.(CVE-2026-26197)