CVE-2026-91129

Home Assistant: mDNS Server-Side Request Forgery

MEDIUM
5.4
CVSS Score
Published: September 22, 2026 at 07:05 PM UTC
Updated: September 25, 2026 at 02:27 PM UTC
1 product affected across 1 vendorHome Assistant

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Severity
MEDIUM5.4
Exploit prediction
EPSS 0.3%
SSVC
PoC

Description

Home Assistant is open source home automation software focused on local control and privacy. Prior to 2026.2.3, the IPP integration automatically processed unauthenticated _ipp._tcp.local mDNS announcements in homeassistant/components/ipp/config_flow.py, where async_step_zeroconf passed attacker-controlled host, port, and base_path values to validate_input for printer metadata retrieval. Because the shared HTTP client followed attacker-controlled cross-origin redirects without blocking loopback targets, a local-network attacker could redirect the request to 127.0.0.1 or another internal service without user interaction or prior IPP configuration. This issue is fixed in version 2026.2.3.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2026.2.3
Affected range stops below 2026.2.3, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.4MEDIUMGitHub_M
Attack Vector
ADJACENT_NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-918

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