CVE-2026-91129: Home Assistant Server-Side Request Forgery in mDNS IPP integration

CVE-2026-91129 · Severity: medium · CVSS 5.4 · Published 2026-09-22

Home Assistant includes an automatic discovery feature for IPP network printers using mDNS (Zeroconf). An attacker on the same local network can broadcast a fake printer announcement that tricks Home Assistant into making HTTP requests to internal services, such as databases or administrative panels, that are not normally accessible from the network. This could expose sensitive data or allow the attacker to interact with internal systems.

Technologies: Home Assistant Home-Assistant, homeassistant (PyPI). Vendors: Home Assistant, PyPI.

Quick answers

Is CVE-2026-91129 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-91129 being exploited in the wild.
How severe is CVE-2026-91129?
Medium severity, with a CVSS score of 5.4, published 22 September 2026.
Which products and versions are affected?
homeassistant (PyPI) < 2026.2.2, ECOSYSTEM:introduced=0,fixed=2026.2.3.
Is there a fix for CVE-2026-91129?
Yes. homeassistant (PyPI): upgrade to 2026.2.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-91129 attacked?
It is attacked from the adjacent network.
Am I affected by CVE-2026-91129?
Check whether you run Home Assistant Home-Assistant or homeassistant (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • homeassistant (PyPI): upgrade to 2026.2.3 or later
    pip install "homeassistant>=2026.2.3"

Technical details

The vulnerability is a Server-Side Request Forgery (SSRF) in the IPP Zeroconf integration (`homeassistant/components/ipp/config_flow.py`). When Home Assistant receives an mDNS announcement for `_ipp._tcp.local` services, it automatically extracts host, port, and path information without validation and makes an HTTP request to verify the printer. The HTTP client blindly follows 302 redirects, allowing an attacker to craft an mDNS response pointing to the attacker's server, which then redirects the request to internal addresses (127.0.0.1 or other localhost-bound services). No authentication or user interaction is required; the integration processes announcements automatically. The fix restricts cross-origin redirects from non-loopback hosts to loopback addresses, blocking DNS-based bypasses as well.

Affected products

  • Home Assistant Home Assistant

Identifiers

  • CVE-2026-91129
  • GHSA-4ghv-53cq-7wp3
  • PYSEC-2026-4051

Timeline

  • 2026-09-22: disclosed
  • other: CVE-2026-91129 assigned

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