# OSV-2020-859: UNKNOWN READ in H5O_sdspace_shared_decode

> A memory corruption vulnerability in the HDF5 library allows attackers to cause a denial of service via crafted files.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Not stated
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 14 Jul 2020

## What is OSV-2020-859?

OSV-2020-859 is a memory corruption vulnerability in matio, published on 14 Jul 2020. 

### Official description

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=19220

```
Crash type: UNKNOWN READ
Crash state:
H5O_sdspace_shared_decode
H5O_attr_shared_decode
H5O_msg_iterate_real
```

## Which versions are affected by OSV-2020-859?

1 open source package ship an affected version, including matio.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `matio` | OSS-Fuzz | All versions | None |

## How do I fix OSV-2020-859?

No fix has been published for OSV-2020-859 yet. Limit exposure of the affected software until one is available.

## Is OSV-2020-859 being exploited?

There is no known exploitation of OSV-2020-859 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for OSV-2020-859 and fix it if it is affected.

What it is: OSV-2020-859 is a memory corruption vulnerability in matio, published on 14 Jul 2020. 
Exploitation: There is no known exploitation of OSV-2020-859 in the wild and no public exploit code.

Affected packages and fixed versions:
- matio (OSS-Fuzz): affected all versions; no fix listed

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/OSV-2020-859/ (Markdown: https://insights.sbomify.com/OSV-2020-859/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/OSV-2020-859

---
From sbomify Insights: https://insights.sbomify.com/OSV-2020-859/
Summaries are generated and may contain mistakes; the official description above is the record.