CVE-2026-19024
Description
A flaw was found in HDF5. A local attacker could exploit a vulnerability in the H5Pget_fill_value function by providing a specially crafted dataset. This could lead to a denial of service, making the system unavailable.
Statement
A flaw was found in the HDF5 library where the H5Pget_fill_value function fails to properly validate and normalize dataset fill value messages. Specifically, when processing a version 1 or version 2 fill value message containing a negative size field alongside an active "defined" flag, the library fails to set the appropriate "undefined" sentinel value. When this unnormalized structure is evaluated, it passes a NULL datatype pointer to H5T_path_find, resulting in a NULL pointer dereference.
To exploit this issue, an attacker must trick a local user or service application linking against the HDF5 library into parsing a specially crafted HDF5 dataset file. Successful exploitation causes the calling application process to terminate abruptly, resulting in a localized denial of service (DoS). Because the vulnerability results strictly in a NULL dereference crash without memory corruption, privilege escalation, or unauthorized data exposure, confidentiality and integrity are unaffected, and the blast radius is confined to the individual parsing process. Due to these reasons, this vulnerability has been rated with a Moderate severity.
Mitigation
To reduce risk prior to patching, restrict processing HDF5 files from untrusted sources, or run file-parsing workflows within isolated, unprivileged worker processes to prevent a potential crash from impacting core operations.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | Required | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
NULL pointer dereferences usually result in the failure of the process unless exception handling (on some platforms) is available and implemented. Even when exception handling is being used, it can still be very difficult to return the software to a safe state of operation.
Integrity,Confidentiality
Technical Impact: Execute Unauthorized Code or Commands; Read Memory; Modify Memory
In rare circumstances, when NULL is equivalent to the 0x0 memory address and privileged code can access it, then writing or reading memory is possible, which may lead to code execution.
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