CVE-2026-19026

Received Received - Intake

Heap Buffer Overflow in HDF5 Library

Publication date: 2026-08-05

Last updated on: 2026-08-05

Assigner: 0253b833-3e77-4dfe-9d57-17db1a2f0a74

Description

H5Z__filter_nbit in H5Znbit.c in HDF5 through 2.3.0 dereferences cd_values[0] through cd_values[4] without validating that cd_values is non-NULL or that cd_nelmts is at least 5, the fixed size of the filter's header. This allows attackers to cause a denial of service via a crafted HDF5 file that stores the N-Bit filter pipeline message with zero client-data values, opened and read via H5Dread, e.g. by the h5ls or h5repack tools.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-08-05

Last Modified

2026-08-05

Generated

2026-08-06

AI Q&A

2026-08-06

EPSS Evaluated

N/A

NVD

CVE-2026-19026

Affected Vendors & Products

Vendor	Product	Version / Range
hdf_group	hdf5	2.3.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-476	The product dereferences a pointer that it expects to be valid but is NULL.
CWE-1284	The product receives input that is expected to specify a quantity (such as size or length), but it does not validate or incorrectly validates that the quantity has the required properties.

Attack-Flow Graph

Executive Summary

This vulnerability involves a flaw in the HDF5 library where the function H5Z__filter_nbit dereferences array elements without checking if the array is non-NULL or if it has enough elements. Attackers can exploit this by creating a malicious HDF5 file with zero client-data values in the N-Bit filter pipeline message. When opened and read using tools like h5ls or h5repack, the vulnerability causes a denial of service.

Detection Guidance

This vulnerability can be detected by attempting to open and read a crafted HDF5 file using tools like h5ls or h5repack. If the system crashes or shows abnormal behavior, it may indicate the presence of this issue.

Impact Analysis

If you use HDF5 files with tools like h5ls or h5repack, an attacker could craft a file that crashes these tools, leading to a denial of service. This could disrupt data processing workflows or analysis tasks that rely on HDF5 files.

Mitigation Strategies

Update HDF5 to a version later than 2.3.0 where this issue has been fixed. Avoid opening untrusted HDF5 files until the update is applied.

Hi! I’m here to help you understand CVE-2026-19026. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70