CVE-2026-34205

Unauthenticated app API access via missing firewall rules

Published Mar 27, 2026 · Updated Mar 27, 2026

Channel restriction failure in Home Assistant Operating System and Supervisor allows remote attackers to access app APIs from the local network. Apps using host network mode share the Linux host namespace, while missing firewall rules leave unauthenticated services on the hassio bridge routable. An attacker on the same local network must route bridge-address traffic through the Home Assistant host and then gains the exposed app's full API functionality.

CVSS severity9.6
Critical
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Channel restriction failure in Home Assistant Operating System and Supervisor allows remote attackers to access app APIs from the local network. Apps using host network mode share the Linux host namespace, while missing firewall rules leave unauthenticated services on the hassio bridge routable. An attacker on the same local network must route bridge-address traffic through the Home Assistant host and then gains the exposed app's full API functionality.

The record

CVE
CVE-2026-34205
Published
Mar 27, 2026
Updated
Mar 27, 2026
Vendor
Home Assistant
Product
Home Assistant Supervisor
Classifications
CWE-923, T1210
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2026.03.2

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Home Assistant · Home Assistant Supervisorversion=< 2026.03.2
Home Assistant · Home Assistant Operating Systemversion=<= 17.1

Published CVSS scores

9.6GitHubCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-923Improper Restriction of Communication Channel to Intended Endpoints
T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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