CVE-2026-88021: Consul vulnerable to an authorization bypass in the Connect service mesh
Consul and Consul Enterprise are vulnerable to an authorization bypass in the Connect service mesh that may allow a service to reach a destination it is not authorized to access. When building Envoy RBAC rules to enforce Connect intentions, Consul did not correctly escape certain characters in service names, namespaces, and partitions, causing the generated authorization rules to match more broadly than intended. This vulnerability (CVE-2026-88021) is fixed in Consul 2.0.4 and Consul Enterprise 1.21.18, 1.22.12 and 2.0.4.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Consulto a version that resolves this vulnerability.Fixed in 2.0.4 - Upgrade
Upgrade
Consul Enterpriseto a version that resolves this vulnerability.Fixed in 1.21.18 - Upgrade
Upgrade
Consul Enterpriseto a version that resolves this vulnerability.Fixed in 1.22.12 - Upgrade
Upgrade
Consul Enterpriseto a version that resolves this vulnerability.Fixed in 2.0.4
Event History
Frequently Asked Questions
What conditions are required for exploitation?
An attacker needs privileges to operate a service within the Connect service mesh and must be able to use specially crafted characters in service names, namespaces, or partitions. The flaw occurs when Consul generates Envoy RBAC rules for Connect intentions.
What is the practical impact?
A service may be able to reach a destination that Connect intentions should prohibit. The affected authorization rules can match more broadly than intended, exposing destination confidentiality and allowing limited integrity impact.
Which releases contain fixes?
The issue is fixed in Consul 2.0.4 and Consul Enterprise 1.21.18, 1.22.12, and 2.0.4.