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🛡️ CVE-2023-6569 — h2o

🔴 CVSS 9.5 — Critical ⚠️ Exploit Public CWE-610 OSV
9.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

External Control of File Name or Path in h2oai/h2o-3

Remote unauthenticated attackers can overwrite arbitrary server files with attacker-controllable data. The data that the attacker can control is not entirely arbitrary. h2o writes a CSV/XLS/etc file to disk, so the attacker data is wrapped in quotations and starts with "C1", if they're exporting as CSV.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality none, integrity low, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:H

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Changed — a successful attack reaches components beyond the vulnerable one.
  • Confidentiality impact: None.
  • Integrity impact: Low — limited, and the attacker does not choose what is affected.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

CVE-2023-6569 is classified as CWE-610: Externally Controlled Reference to a Resource in Another Sphere. The product uses an externally controlled name or reference that resolves to a resource that is outside of the intended control sphere.

Affected software

CVE-2023-6569 is recorded against 1 package.

  • h2o (fixed in 3.46.0.1)

Timeline and source

Published on 29 June 2026 and last revised on 1 July 2026. A public exploit is known to exist, which raises the urgency of patching considerably. Record sourced from OSV.

References

nvd.nist.gov (Advisory)
github.com (Web)
github.com (Package)
huntr.com (Web)
pypi.org (Package)
github.com (Advisory)

Other advisories for this package

h2o has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-610: Externally Controlled Reference to a Resource in Another Sphere) in other software:

Details

Severity CRITICAL
CVSS Score 9.5
CVSS Vector CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:H
CWE CWE-610
Public Exploit ⚠️ Yes
Source OSV
Published 2026-06-29
Updated 2026-08-20
Modified 2026-07-01
Fix URL N/A

Affected Packages

Software From version Fixed in
h2o — 3.46.0.1

Similar Threats

Exploit Protection

Are you running h2o?

CVE-2023-6569 carries CVSS 9.5 Critical rating and a public exploit already exists. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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