CVE-2026-84716 Automation-controller: automation-controller: instance install_bundle issues 10-year, non-revocable receptor mesh-ca certificates for caller-chosen (and case-variant impersonating) hostnames

Description

A flaw was found in the automation-controller instance install-bundle endpoint. When a System Administrator downloads an execution/hop node's install bundle, the controller signs an X.509 certificate with the receptor mesh certificate authority in which the Common Name, DNS subject-alternative-name, and receptor node-id are taken verbatim from the caller-chosen instance hostname, with a hard-coded ten-year validity, a random serial, and no issuance log or revocation list. Because the hostname charset validator is case-insensitive while the uniqueness validator is case-sensitive, an administrator can register a case variant of an existing control node's hostname and obtain a mesh-CA-signed certificate that TLS peers, which match hostnames case-insensitively, accept as that control node. In managed/hosted deployments — where the customer holds controller superuser but the platform operator runs the mesh — this yields a long-lived, non-revocable mesh peer credential and, with an on-path position, TLS impersonation or interception of control/hybrid mesh nodes. It does not grant direct remote code execution, because receptor work submission is gated by a separate signing key not included in the bundle.

Exploitable remotely over the network, with an administrator account and without any user action; an attacker can seriously compromise confidentiality, integrity or availability.

Attack vector

Network

Attack complexity

High

Privileges required

High

Interaction

None

Scope

Changed

Confidentiality

High

Integrity

Low

Availability

None

Affected products and versions