H2O has an External Control of File Name or Path vulnerability
Critical severity
GitHub Reviewed
Published
Feb 2, 2026
to the GitHub Advisory Database
•
Updated Feb 2, 2026
Description
Published by the National Vulnerability Database
Feb 2, 2026
Published to the GitHub Advisory Database
Feb 2, 2026
Reviewed
Feb 2, 2026
Last updated
Feb 2, 2026
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/Parseendpoint to inject attacker-controlled data as the header of an empty file, which is then exported using the/3/Frames/framename/exportendpoint. 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.References