v1.15.6

## 1.15.6
### February 29, 2024

SECURITY:

* auth/cert: compare public keys of trusted non-CA certificates with incoming
client certificates to prevent trusting certs with the same serial number
but not the same public/private key. [[GH-25649](https://github.com/hashicorp/vault/pull/25649)]

CHANGES:

* core: Bump Go version to 1.21.7.
* secrets/openldap: Update plugin to v0.12.1 [[GH-25524](https://github.com/hashicorp/vault/pull/25524)]

FEATURES:

* **Manual License Utilization Reporting**: Added manual license
utilization reporting, which allows users to create manual exports of product-license [metering
data] to report to Hashicorp.

IMPROVEMENTS:

* auth/cert: Cache trusted certs to reduce memory usage and improve performance of logins. [[GH-25421](https://github.com/hashicorp/vault/pull/25421)]
* ui: Add `deletion_allowed` param to transformations and include `tokenization` as a type option [[GH-25436](https://github.com/hashicorp/vault/pull/25436)]
* ui: redirect back to current route after reauthentication when token expires [[GH-25335](https://github.com/hashicorp/vault/pull/25335)]
* ui: remove unnecessary OpenAPI calls for unmanaged auth methods [[GH-25364](https://github.com/hashicorp/vault/pull/25364)]

BUG FIXES:

* agent: Fix issue where Vault Agent was unable to render KVv2 secrets with delete_version_after set. [[GH-25387](https://github.com/hashicorp/vault/pull/25387)]
* audit: Handle a potential panic while formatting audit entries for an audit log [[GH-25605](https://github.com/hashicorp/vault/pull/25605)]
* core (enterprise): Fix a deadlock that can occur on performance secondary clusters when there are many mounts and a mount is deleted or filtered [[GH-25448](https://github.com/hashicorp/vault/pull/25448)]
* core (enterprise): Fix a panic that can occur if only one seal exists but is unhealthy on the non-first restart of Vault.
* core/quotas: Deleting a namespace that contains a rate limit quota no longer breaks replication [[GH-25439](https://github.com/hashicorp/vault/pull/25439)]
* openapi: Fixing response fields for rekey operations [[GH-25509](https://github.com/hashicorp/vault/pull/25509)]
* secrets/transit: When provided an invalid input with hash_algorithm=none, a lock was not released properly before reporting an error leading to deadlocks on a subsequent key configuration update. [[GH-25336](https://github.com/hashicorp/vault/pull/25336)]
* storage/file: Fixing spuriously deleting storage keys ending with .temp [[GH-25395](https://github.com/hashicorp/vault/pull/25395)]
* transform (enterprise): guard against a panic looking up a token in exportable mode with barrier storage.
* ui: Do not disable JSON display toggle for KV version 2 secrets [[GH-25235](https://github.com/hashicorp/vault/pull/25235)]
* ui: Do not show resultant-acl banner on namespaces a user has access to [[GH-25256](https://github.com/hashicorp/vault/pull/25256)]
* ui: Fix copy button not working on masked input when value is not a string [[GH-25269](https://github.com/hashicorp/vault/pull/25269)]
* ui: Update the KV secret data when you change the version you're viewing of a nested secret. [[GH-25152](https://github.com/hashicorp/vault/pull/25152)]