# CVE-2024-5986: Remote Arbitrary File Write with Arbitrary Data in h2oai/h2o-3

> Remote attackers can write arbitrary data to any file on the server via the Parse and export endpoints, potentially leading to remote code execution.

- **Severity:** Critical 9.1 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 2 Feb 2026
- **Updated:** 2 Feb 2026
- **Also known as:** GHSA-wj3h-wx8g-x699, PYSEC-2026-353

## What is CVE-2024-5986?

CVE-2024-5986 is a critical path traversal vulnerability in h2oai/h2o-3, published on 2 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in h2oai/h2o-3 version 3.46.0.1 allows remote attackers to write arbitrary data to any file on the server. This is achieved by exploiting the `/3/Parse` endpoint to inject attacker-controlled data as the header of an empty file, which is then exported using the `/3/Frames/framename/export` endpoint. The impact of this vulnerability includes the potential for remote code execution and complete access to the system running h2o-3, as attackers can overwrite critical files such as private SSH keys or script files.

Weakness: CWE-73 (External Control of File Name or Path)

## Which versions are affected by CVE-2024-5986?

5 open source packages ship an affected version, including h2o and ai.h2o:h2o-core.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `h2o` | PyPI | All versions to 3.46.0.1 | None |
| `h2o` | PyPI | All versions to 3.46.0.1 | None |
| `h2o` | PyPI | All versions to 3.46.0.1 | None |
| `ai.h2o:h2o-core` | Maven | All versions to 3.46.0.1 | None |
| `ai.h2o:h2o-core` | Maven | All versions to 3.46.0.1 | None |

## How do I fix CVE-2024-5986?

No fix has been published for CVE-2024-5986 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-5986 being exploited?

There is no known exploitation of CVE-2024-5986 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-5986 and fix it if it is affected.

What it is: CVE-2024-5986 is a critical path traversal vulnerability in h2oai/h2o-3, published on 2 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-5986 in the wild and no public exploit code.

Affected packages and fixed versions:
- h2o (PyPI): affected all versions up to 3.46.0.1; no fix listed
- h2o (PyPI): affected all versions up to 3.46.0.1; no fix listed
- h2o (PyPI): affected all versions up to 3.46.0.1; no fix listed
- ai.h2o:h2o-core (Maven): affected all versions up to 3.46.0.1; no fix listed
- ai.h2o:h2o-core (Maven): affected all versions up to 3.46.0.1; 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/CVE-2024-5986/ (Markdown: https://insights.sbomify.com/CVE-2024-5986/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-5986
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-5986
- OSV: https://osv.dev/vulnerability/CVE-2024-5986

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-5986/
Summaries are generated and may contain mistakes; the official description above is the record.