# CVE-2026-19024: HDF5 H5Pget_fill_value NULL Pointer Dereference via Malformed Fill Value Message

> Attackers can cause denial of service in HDF5 by providing a malformed fill value message with a negative size field.

- **Severity:** High 8.2 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 5 Aug 2026
- **Updated:** 6 Aug 2026
- **Also known as:** AZL-94505, DEBIAN-CVE-2026-19024, ECHO-15c1-bb78-dbe9, GHSA-c7cf-qx8c-5ph7, RHSA-2026:79131, UBUNTU-CVE-2026-19024

## What is CVE-2026-19024?

CVE-2026-19024 is a high-severity vulnerability in The HDF Group HDF5, published on 5 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

NULL pointer dereference in H5Pget_fill_value in HDF5 before 2.3.0 allows attackers to cause a denial of service via a dataset whose version 1 or 2 fill value message has the "defined" flag set together with a negative size field, which is not normalized to the library's "undefined" sentinel and reaches H5T_path_find with a NULL datatype.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-19024?


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `hdf5` | Red Hat:hummingbird:1 | All versions | 0:2.2.0-0.1.3.hum1 |
| `hdf5-devel` | Red Hat:hummingbird:1 | All versions | 0:2.2.0-0.1.3.hum1 |
| `hdf5-mpich` | Red Hat:hummingbird:1 | All versions | 0:2.2.0-0.1.3.hum1 |
| `hdf5-mpich-devel` | Red Hat:hummingbird:1 | All versions | 0:2.2.0-0.1.3.hum1 |
| `hdf5-mpich-static` | Red Hat:hummingbird:1 | All versions | 0:2.2.0-0.1.3.hum1 |
| `hdf5-openmpi` | Red Hat:hummingbird:1 | All versions | 0:2.2.0-0.1.3.hum1 |
| `hdf5-openmpi-devel` | Red Hat:hummingbird:1 | All versions | 0:2.2.0-0.1.3.hum1 |
| `hdf5-openmpi-static` | Red Hat:hummingbird:1 | All versions | 0:2.2.0-0.1.3.hum1 |
| `hdf5-static` | Red Hat:hummingbird:1 | All versions | 0:2.2.0-0.1.3.hum1 |
| `java-hdf5` | Red Hat:hummingbird:1 | All versions | 0:2.2.0-0.1.3.hum1 |

## How do I fix CVE-2026-19024?

Upgrade to a fixed version.

## Is CVE-2026-19024 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-19024 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-19024 and fix it if it is affected.

What it is: CVE-2026-19024 is a high-severity vulnerability in The HDF Group HDF5, published on 5 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-19024 exists.

Affected product: The HDF Group HDF5. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-19024/ (Markdown: https://insights.sbomify.com/CVE-2026-19024/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-19024
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-19024
- OSV: https://osv.dev/vulnerability/CVE-2026-19024

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-19024/
Summaries are generated and may contain mistakes; the official description above is the record.