CVE-2023-27594: Cilium vulnerable to potential network policy bypass when routing IPv6 traffic

Vulnerability summary

CVE-2023-27594 is a high (CVSS 7.3) Improper Authorization vulnerability in cilium. EPSS estimates a 0.55% chance of exploitation in the next 30 days, higher than 45.3% of scored vulnerabilities.

Timeline

1. 17-03-2023
   PublishedVulnerability first disclosed.
2. 25-02-2025
   Last modifiedVulnerability information updated.

Description

Cilium is a networking, observability, and security solution with an eBPF-based dataplane. Prior to versions 1.11.15, 1.12.8, and 1.13.1, under specific conditions, Cilium may misattribute the source IP address of traffic to a cluster, identifying external traffic as coming from the host on which Cilium is running. As a consequence, network policies for that cluster might be bypassed, depending on the specific network policies enabled. This issue only manifests when Cilium is routing IPv6 traffic and NodePorts are used to route traffic to pods. IPv6 and endpoint routes are both disabled by default. The problem has been fixed and is available on versions 1.11.15, 1.12.8, and 1.13.1. As a workaround, disable IPv6 routing.

• CWE-285Improper AuthorizationThe product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.
• CWE-863Incorrect AuthorizationThe product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.