High [CVE-2026-12383] ExternalEventStreamViewSet trusts Subject header without validation and leaks expected DN
This high-severity Red Hat Linux advisory covers CVE-2026-12383 affecting Red Hat Ansible Automation Platform 2.5 for RHEL 8, Red Hat Ansible Automation Platform 2.5 for RHEL 9, Red Hat Ansible Automation Platform 2.6 for RHEL 9.
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Summary
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). 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.
Red Hat severity: Important — CVSS 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N). Weakness: CWE-345.
Affected Red Hat products: Red Hat Ansible Automation Platform 2.5 for RHEL 8; Red Hat Ansible Automation Platform 2.5 for RHEL 9; Red Hat Ansible Automation Platform 2.6 for RHEL 9; Red Hat Ansible Automation Platform 2.7.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.
Official advisory · high-confidence parse· fetched 26 days ago·verify at source
- automation-eda-controller-0:1.1.21-1.el8ap
- automation-eda-controller-0:1.1.21-1.el9ap
- automation-eda-controller-0:1.2.11-1.el9ap
- ansible-automation-platform-27/eda-controller-rhel9:1785374869
- RHSA-2026:50319
- RHSA-2026:50336
- RHSA-2026:50340
Official advisory · high-confidence parse· fetched 26 days ago·verify at source
Mitigation checklist
- 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.
Official advisory · high-confidence parse· fetched 26 days ago·verify at source
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