CVE-2026-19026: CWE-476 NULL pointer dereference in The HDF Group HDF5
CVE-2026-19026 is a medium severity vulnerability in The HDF Group's HDF5 library up to version 2.3.0. It involves a NULL pointer dereference in the N-Bit filter implementation, where the code dereferences elements of a client-data array without validating its presence or size. This flaw can be triggered by processing a crafted HDF5 file containing a malformed N-Bit filter pipeline message, leading to a denial of service when reading data with functions like H5Dread or tools such as h5ls or h5repack.
AI Analysis
Technical Summary
The vulnerability exists in the function H5Z__filter_nbit within H5Znbit.c of the HDF5 library versions up to 2.3.0. The function dereferences the cd_values array indices 0 through 4 without checking if cd_values is NULL or if the number of elements cd_nelmts is at least 5, which is required for the filter's header. An attacker can exploit this by crafting an HDF5 file that includes an N-Bit filter pipeline message with zero client-data values. When this file is opened and read using H5Dread or related tools, it causes a NULL pointer dereference, resulting in a denial of service.
Potential Impact
Successful exploitation causes a denial of service due to NULL pointer dereference when processing maliciously crafted HDF5 files. There is no indication of code execution or data corruption beyond service disruption. The vulnerability requires local access to open the crafted file and user interaction to trigger the issue.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, avoid opening untrusted or suspicious HDF5 files that may contain malformed N-Bit filter pipeline messages. Monitor vendor communications for updates on patches or official mitigations.
CVE-2026-19026: CWE-476 NULL pointer dereference in The HDF Group HDF5
Description
CVE-2026-19026 is a medium severity vulnerability in The HDF Group's HDF5 library up to version 2.3.0. It involves a NULL pointer dereference in the N-Bit filter implementation, where the code dereferences elements of a client-data array without validating its presence or size. This flaw can be triggered by processing a crafted HDF5 file containing a malformed N-Bit filter pipeline message, leading to a denial of service when reading data with functions like H5Dread or tools such as h5ls or h5repack.
CVSS v4.0
Score 6.8medium
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability exists in the function H5Z__filter_nbit within H5Znbit.c of the HDF5 library versions up to 2.3.0. The function dereferences the cd_values array indices 0 through 4 without checking if cd_values is NULL or if the number of elements cd_nelmts is at least 5, which is required for the filter's header. An attacker can exploit this by crafting an HDF5 file that includes an N-Bit filter pipeline message with zero client-data values. When this file is opened and read using H5Dread or related tools, it causes a NULL pointer dereference, resulting in a denial of service.
Potential Impact
Successful exploitation causes a denial of service due to NULL pointer dereference when processing maliciously crafted HDF5 files. There is no indication of code execution or data corruption beyond service disruption. The vulnerability requires local access to open the crafted file and user interaction to trigger the issue.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, avoid opening untrusted or suspicious HDF5 files that may contain malformed N-Bit filter pipeline messages. Monitor vendor communications for updates on patches or official mitigations.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- HDFG
- Date Reserved
- 2026-08-05T22:14:40.349Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a73bfadbf8831d53994ed48
Added to database: 08/05/2026, 22:56:45 UTC
Last enriched: 08/05/2026, 23:16:17 UTC
Last updated: 08/05/2026, 23:20:06 UTC
Views: 4
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