H2O has an External Control of File Name or Path vulnerability

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

9.1 · CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

EPSS

• CVE-2024-5986: 0.70% estimated exploitation activity in the next 30 days; percentile 53.36 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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.

Published by the source

2 Feb 2026, 12:31 UTC

Last modified by the source

27 Oct 2026, 16:45 UTC

Source last checked

28 Oct 2026, 06:05 UTC

1. Revision 5 · amended · 28 Oct 2026

   Amended from osv record GHSA-wj3h-wx8g-x699

2. Revision 4 · amended · 27 Oct 2026

   Amended from ghsa record GHSA-wj3h-wx8g-x699

3. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-wj3h-wx8g-x699

4. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-wj3h-wx8g-x699

5. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-wj3h-wx8g-x699

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# Patch Next advisory brief: CVE-2024-5986

Advisory: H2O has an External Control of File Name or Path vulnerability
IDs: CVE-2024-5986, GHSA-wj3h-wx8g-x699
Record: https://patchnext.com/advisories/cve-2024-5986 (revision 5, source checked 28 Oct 2026, 06:05 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI h2o: affected <= 3.46.0.1
- Maven ai.h2o:h2o-core: affected <= 3.46.0.1

## Suggested inspection (read-only)
- `python -m pip show h2o`: prints the installed version. Run with the environment that serves production active.
- Maven ai.h2o:h2o-core: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on h2o, ai.h2o:h2o-core.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-wj3h-wx8g-x699 (GitHub-reviewed advisory GHSA-wj3h-wx8g-x699 lists affected ranges: PyPI h2o >=0 <=3.46.0.1)
- Verified: https://osv.dev/vulnerability/GHSA-wj3h-wx8g-x699 (OSV record GHSA-wj3h-wx8g-x699 lists affected ranges: Maven ai.h2o:h2o-core >=0 =0 <=3.46.0.1)
- Verified: https://github.com/advisories/GHSA-wj3h-wx8g-x699 (GitHub-reviewed advisory GHSA-wj3h-wx8g-x699 lists affected ranges: Maven ai.h2o:h2o-core >=0 =0 <=3.46.0.1)

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