# CVE-2026-17573: Double Free in H5D__chunk_copy() in HDF5 via a Crafted Chunk-Index Size Field

> A double free vulnerability in the HDF5 library allows attackers to cause a denial of service via a crafted file processed by h5repack.

- **Severity:** Medium 4.0 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U`)
- **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:** 27 Jul 2026
- **Updated:** 27 Jul 2026
- **Also known as:** AZL-94013, DEBIAN-CVE-2026-17573, ECHO-9710-769a-b90b, GHSA-3536-73hp-9xm7, JLSEC-2026-1385, UBUNTU-CVE-2026-17573

## What is CVE-2026-17573?

CVE-2026-17573 is a medium-severity use after free vulnerability in Hdfgroup Hdf5, published on 27 Jul 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

A double free vulnerability was discovered in the HDF5 library. Processing a crafted HDF5 file containing an oversized chunk size field via h5repack may cause the application to abort due to a double free.

Weakness: CWE-415 (Double Free)

## Which versions are affected by CVE-2026-17573?

It affects 1 product.


Products: Hdfgroup Hdf5.

## How do I fix CVE-2026-17573?

Apply the vendor's patch.

## Is CVE-2026-17573 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-17573 exists.

## Other vulnerabilities in Hdfgroup Hdf5

- [CVE-2024-32608](https://insights.sbomify.com/CVE-2024-32608/): Memory corruption in n/a (critical 9.8)
- [CVE-2024-29157](https://insights.sbomify.com/CVE-2024-29157/): Memory corruption in n/a (critical 9.8)
- [CVE-2024-29159](https://insights.sbomify.com/CVE-2024-29159/): Memory corruption in n/a (critical 9.8)
- [CVE-2024-29164](https://insights.sbomify.com/CVE-2024-29164/): Memory corruption in n/a (critical 9.8)
- [CVE-2024-32611](https://insights.sbomify.com/CVE-2024-32611/): Other in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-17573 and fix it if it is affected.

What it is: CVE-2026-17573 is a medium-severity use after free vulnerability in Hdfgroup Hdf5, published on 27 Jul 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-2026-17573 exists.

Affected product: Hdfgroup 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-2026-17573/ (Markdown: https://insights.sbomify.com/CVE-2026-17573/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-17573
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-17573
- OSV: https://osv.dev/vulnerability/CVE-2026-17573

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-17573/
Summaries are generated and may contain mistakes; the official description above is the record.