# CVE-2026-106547: HDF5 heap-based buffer overflow in H5VM_array_fill

Source: https://junglewise.ai/threats/cve-2026-106547-a-heap-based-buffer-overflow-in-h5vm-array-fill-in-src-h5vm-c-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-06. Updated: 2026-10-06  
License: CC BY 4.0 with a link back

CVE-2026-106547 · Severity: info · Published 2026-10-06

HDF5 is a library used by scientific and data analysis applications to store and manage large amounts of data. A heap-based buffer overflow in how HDF5 processes dataset fill values could allow an attacker to crash an application or potentially execute arbitrary code by crafting a malicious HDF5 file with inconsistent metadata.

Technologies: [HDF Group HDF5](https://junglewise.ai/threats/technologies/hdf-group-hdf5). Vendors: [HDF Group](https://junglewise.ai/threats/vendors/hdf-group).

## Quick answers

**Is CVE-2026-106547 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-106547 being exploited in the wild.

**How severe is CVE-2026-106547?** Informational severity, published 6 October 2026.

**Which products and versions are affected?** HDF Group HDF5 before 2.2.0.

**Is there a fix for CVE-2026-106547?** Yes: fixed in HDF5 2.2.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-106547 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-106547?** Check whether you run HDF Group HDF5 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in HDF5 2.2.0

## Technical details

A heap-based buffer overflow occurs in H5VM_array_fill() when H5D__fill_init() writes a fill-value buffer without validating that the datatype and dataspace metadata are consistent with the allocated buffer size. An attacker can craft an HDF5 file where this metadata mismatch causes a write past the buffer boundary, with the attacker controlling the written content through the fill value in the file. The vulnerability affects remote code execution scenarios where untrusted HDF5 files are processed.

## Affected products

- HDF Group HDF5 before 2.2.0

## Timeline

- 2026-10-06: disclosed
- 2026-07-17: patched

## References

- [https://github.com/HDFGroup/hdf5/pull/6529](https://github.com/HDFGroup/hdf5/pull/6529)

## Related threats

- [HDF5 heap buffer over-read in external link traversal](https://junglewise.ai/threats/cve-2026-120757-hdf5-through-2-2-0-contains-a-heap-buffer-over-read)
- [HDF5 uninitialized memory read in scaleoffset filter](https://junglewise.ai/threats/cve-2026-120754-hdf5-through-2-2-0-contains-an-uninitialized-memory-read)
- [HDF5 heap buffer over-read in scale-offset filter decode](https://junglewise.ai/threats/cve-2026-19029-a-heap-based-buffer-over-read-in-h5z-filter-scaleoffset-in-src)