High [CVE-2026-14362] HashiCorp memberlist: Denial of Service via push/pull state handling

HashiCorp memberlist before version 0.6.0 is vulnerable to a denial-of-service issue in its push/pull state handling that may allow an attacker with network access to the gossip port to exhaust memory on a receiving node and cause the process to terminate. This vulnerability (CVE-2026-14362) is fixed in memberlist 0.6.0.

This flaw results in a Denial of Service (DoS). Only Red Hat products that run the affected component as a live memberlist gossip agent (a process that binds and listens on a UDP/TCP gossip port for cluster membership) are exposed to this denial-of-service issue.

Products that pull in github.com/hashicorp/memberlist only as a transitive Go dependency, without starting a gossip listener, do not exercise the vulnerable push/pull state-handling code path and are not affected.

Grafana links github.com/hashicorp/memberlist solely for its optional unified-alerting high-availability (HA) clustering feature; the gossip listener only starts when unified_alerting.ha_peers (plus ha_listen_address/ha_advertise_address) is explicitly configured.

Red Hat Advanced Cluster Management for Kubernetes ships its acm-grafana component with unified alerting disabled by default (unified_alerting.enabled = false) and never sets ha_peers, so it never starts the gossip listener and does not exercise the vulnerable code path; it is not affected.