Copyright © 2012 Red Hat, Inc. All rights reserved. Important 2026-07-27T19:04:53 eda-server: ExternalEventStreamViewSet trusts Subject header without validation and leaks expected DN 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N CWE-345

A flaw was found in the Event-Driven Ansible (EDA) server. The ExternalEventStreamViewSet uses permissive access controls (permission_classes=[AllowAny], authentication_classes=[]) and relies solely on the Subject HTTP header value for mTLS authentication without verifying that the header originated from a trusted proxy. Additionally, the expected certificate Distinguished Name is leaked in the 403 error response body. An attacker who can reach the EDA API endpoint with a spoofed Subject header can inject arbitrary events into mTLS-protected event streams, triggering downstream automation actions.

A flaw was found in the Event-Driven Ansible (EDA) server. The ExternalEventStreamViewSet uses permissive access controls (permission_classes=[AllowAny], authentication_classes=[]) and relies solely on the Subject HTTP header value for mTLS authentication without verifying that the header originated from a trusted proxy. Additionally, the expected certificate Distinguished Name is leaked in the 403 error response body. An attacker who can reach the EDA API endpoint with a spoofed Subject header can inject arbitrary events into mTLS-protected event streams, triggering downstream automation actions.

This flaw is a defense-in-depth failure in EDA that becomes exploitable when combined with the gateway header-forwarding issue (tracked as a separate CVE). EDA should not rely solely on an HTTP header for mTLS authentication. The DN leak in the error response further reduces the difficulty of exploitation. EDA has been included in AAP since version 2.4. The mTLS external event stream feature and the trust-of-Subject-header pattern apply to all EDA versions that support external event streams with mTLS authentication. This issue was discovered by Chris Meyers (Red Hat). The following practices would help for avoiding exposure and mitigate this flaw: - Ensure the EDA server is not directly accessible from untrusted networks; all traffic should route through the AAP Gateway which should perform mTLS validation. - If possible, configure network-level access controls to restrict which source IPs can reach the EDA backend API. - Monitor EDA event streams for unexpected events_received counter changes. - Review and rotate mTLS client certificates if unauthorized access is suspected, as the expected DN may have been leaked via the 403 error response. Red Hat Ansible Automation Platform 2.5 for RHEL 8 2026-08-04T00:00:00Z RHSA-2026:50319 automation-eda-controller-0:1.1.21-1.el8ap Red Hat Ansible Automation Platform 2.5 for RHEL 9 2026-08-04T00:00:00Z RHSA-2026:50319 automation-eda-controller-0:1.1.21-1.el9ap Red Hat Ansible Automation Platform 2.6 for RHEL 9 2026-08-04T00:00:00Z RHSA-2026:50336 automation-eda-controller-0:1.2.11-1.el9ap Red Hat Ansible Automation Platform 2.7 2026-08-04T00:00:00Z RHSA-2026:50340 ansible-automation-platform-27/eda-controller-rhel9:1785374869 https://www.cve.org/CVERecord?id=CVE-2026-12383 https://nvd.nist.gov/vuln/detail/CVE-2026-12383