PT-2026-53442 · Pypi · H2O

Published 2026-06-29 · Updated 2026-06-29

OSV

CVSS v3.1

9.1

Critical

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

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.

Fix

Related Identifiers

PYSEC-2026-353

Affected Products

H2O

References · 6

• https://nvd.nist.gov/vuln/detail/CVE-2024-5986 · Security Note
• https://osv.dev/vulnerability/PYSEC-2026-353 · Vendor Advisory
• https://github.com/h2oai/h2o-3 · Note
• https://pypi.org/project/h2o · Note
• https://huntr.com/bounties/64ff5319-6ac3-4447-87f7-b53495d4d5a3 · Note
• https://github.com/advisories/GHSA-wj3h-wx8g-x699 · Note