OpenStack Designate Cross-Tenant DNS Region Overlap and mDNS DoS (CVE-2026-71193/194)

Vulnerability Overview Vulnerability Name: OpenStack Designate Cross-Tenant DNS Overlap and mDNS DoS Vulnerability CVE ID: CVE-2026-71193, CVE-2026-71194 Publication Date: August 11, 2026 Affected Component: OpenStack Designate Vulnerability Description: OpenStack Designate fails to enforce cross-pool region ownership checks when scheduling regions to non-default pools. Tenants can target different pools by creating sub-regions, super-regions, or copying another tenant's regions using attribute pools, leading to DNS hijacking or denial of service. Additionally, Red Hat's mDNS handler performs pool-blind record lookups, resulting in deterministic denial of service between pools with conflicting regions. Impact Scope Affected Versions: - >=1.0.0 =21.0.0 <22.0.0 Remediation Patch Links: - https://review.opendev.org/1000475 (2025 /apoxy) - https://review.opendev.org/1000474 (2025 /flamungo) - https://review.opendev.org/1000473 (2025 /garpzcuc) - https://review.opendev.org/1000471 (2026 /hibiscus (development)) Notes: - Stable branch patches depend on two prerequisite backports (mDNS Split-Scope for Pool Scope). Changes 998065/998086 and their stable equivalents were merged prior to disclosure. Operators must ensure these prerequisite commits are present before applying the fix. - Operators should audit existing regions to detect cross-tenant conflicts that may have been created before the fix. A detection tool will be proposed as a separate public patch. References https://launchpad.net/bugs/2160533 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-71193 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-71194 Additional Information Authors: Tore Anderson from Redpill Linpro AS, Omer Schwartz from Red Hat Contact Email: oss-security@lists.openwall.com Mailing List: OpenStack Vulnerability Management Team

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OpenStack Designate Cross-Tenant DNS Region Overlap and mDNS DoS (CVE-2026-71193/194)