CVE-2023-3518: 
Consul vulnerability analysis and mitigation

HashiCorp Consul and Consul Enterprise 1.16.0 contained a vulnerability (CVE-2023-3518) in the JWT authentication mechanism for service mesh that incorrectly allowed or denied access regardless of service identities. The vulnerability was discovered through internal testing by the Consul engineering team and was fixed in version 1.16.1 (HashiCorp Advisory).

The vulnerability affects the JWT authentication implementation for service mesh introduced in Consul 1.16.0. The issue allows two source intentions that would restrict access to an endpoint with differing JWT providers to cause only one JWT validation configuration to be used. This could result in some service identities being allowed with mismatching JWTs. The vulnerability has been assigned a CVSS v3.1 base score of 7.3 (HIGH) with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L (NVD).

The vulnerability could allow unauthorized access to services within the mesh by bypassing intended JWT authentication controls. This could potentially lead to unauthorized access to sensitive endpoints and compromise of service mesh security controls (HashiCorp Advisory).

Users should upgrade to Consul version 1.16.1 or newer to address this vulnerability. HashiCorp has provided upgrade guidance in their Consul's Upgrading documentation. Organizations should evaluate the risk associated with this issue and prioritize the upgrade accordingly (HashiCorp Advisory).