CyberSecBulletin
CVE-2023-41899NVD status: Modified

core: Server-Side Request Forgery

Published Updated By the CyberSecBulletin desk

CVE-2023-41899 is a high-severity server-side request forgery vulnerability in core from Home-assistant, with a CVSS 3.1 base score of 7.2 out of 10. It can be exploited remotely over the network by an attacker with administrator privileges, without any action from a user. Affected core versions: < 2023.9.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.56% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Home-assistant to 2023.9.0 or a later version.
  2. Read the advisory on github.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
Home-assistantcore< 2023.9.0Not stated
Home-assistantHome-assistantbefore 2023.9.02023.9.0

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
HighAdministrator-level access is required first.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.16.6MediumCNA (github.com)
CVSS 3.17.2HighNVD

Official description

Home assistant is an open source home automation. In affected versions the `hassio.addon_stdin` is vulnerable to a partial Server-Side Request Forgery where an attacker capable of calling this service (e.g.: through GHSA-h2jp-7grc-9xpp) may be able to invoke any Supervisor REST API endpoints with a POST request. An attacker able to exploit will be able to control the data dictionary, including its addon and input key/values. This issue has been addressed in version 2023.9.0 and all users are advised to upgrade. There are no known workarounds for this vulnerability. This issue is also tracked as GitHub Security Lab (GHSL) Vulnerability Report: `GHSL-2023-162`.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Server-Side Request Forgery

The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

How developers prevent this class of flaw

  • If there is a known list of applications, IP, hostname, and/or domains to which the product is allowed to communicate, then use allowlists to ensure that outgoing requests are restricted to these known entities. The allowlists could be in the application code or possibly enforced by firewalls or network segmentation.
  • If the product is expected to be able to connect to arbitrary IP addresses or domains, consider using a denylist that includes private network addresses, internal domain names, etc. The denylist could be in the application code or possibly enforced by firewalls or network segmentation.

More Server-Side Request Forgery vulnerabilities (CWE-918)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in core

All core vulnerabilities

Recent Server-Side Request Forgery vulnerabilities

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