# CVE-2025-6858: HDF5 H5Centry.c H5C__flush_single_entry null pointer dereference

> A local attacker can cause a denial of service via null pointer dereference in the HDF5 library's cache entry flushing function.

- **Severity:** Medium 4.8 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 29 Jun 2025
- **Updated:** 30 Jun 2025
- **Also known as:** AZL-64407, AZL-64428, DEBIAN-CVE-2025-6858, ECHO-c189-e8df-c780, GHSA-8fpg-65fw-rjmf, JLSEC-2026-348, UBUNTU-CVE-2025-6858

## What is CVE-2025-6858?

CVE-2025-6858 is a medium-severity vulnerability in Hdfgroup Hdf5, published on 29 Jun 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability was found in HDF5 1.14.6 and classified as problematic. Affected by this issue is the function H5C__flush_single_entry of the file src/H5Centry.c. The manipulation leads to null pointer dereference. The attack needs to be approached locally. The exploit has been disclosed to the public and may be used.

Weakness: CWE-476 (NULL Pointer Dereference), CWE-404 (Improper Resource Shutdown or Release)

## Which versions are affected by CVE-2025-6858?

It affects 1 product.


Products: Hdfgroup Hdf5.

## How do I fix CVE-2025-6858?

Upgrade to a fixed version.

## Is CVE-2025-6858 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-6858 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-2025-6858 and fix it if it is affected.

What it is: CVE-2025-6858 is a medium-severity vulnerability in Hdfgroup Hdf5, published on 29 Jun 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-6858 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-2025-6858/ (Markdown: https://insights.sbomify.com/CVE-2025-6858/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-6858
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-6858
- OSV: https://osv.dev/vulnerability/CVE-2025-6858

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-6858/
Summaries are generated and may contain mistakes; the official description above is the record.