### Fatal error during expiration metrics gathering causing Vault crash

#### Affected versions

This issue affects Vault Community and Enterprise versions:
- 1.13.9
- 1.14.5
- 1.15.1

A fix has been issued in Vault 1.13.10, 1.14.6, and 1.15.2.

#### Issue

A recent change to Vault to improve state change speed (e.g. becoming active or standby) introduced a concurrency issue
which can lead to a concurrent iteration and write on a map, causing a fatal error and crashing Vault. This error occurs
when gathering lease and token metrics from the expiration manager. These metrics originate from the active node in a HA
cluster, as such a standby node will take over active duties and the cluster will remain functional should the original
active node encounter this bug. The new active node will be vulnerable to the same bug, but may not encounter it immediately.

There is no workaround.


