8.18.1 release notes (#6802) (#6829)

* First draft

* Revisions

* Update docs/release-notes/8.18.asciidoc

Co-authored-by: Gabriel Landau <[email protected]>

* Update docs/release-notes/8.18.asciidoc

Co-authored-by: Gabriel Landau <[email protected]>

* Update docs/release-notes/8.18.asciidoc

Co-authored-by: Gabriel Landau <[email protected]>

* Adds 216667

* space

* Update ki description for endpoint bug

* Adds ki about eql rules

* remove char

* Adds one more version

---------

Co-authored-by: Gabriel Landau <[email protected]>
(cherry picked from commit 67a4f7e)

Co-authored-by: Nastasha Solomon <[email protected]>

Author: mergify[bot]

docs/release-notes.asciidoc

@@ -3,6 +3,7 @@
 
 This section summarizes the changes in each release.
 
+* <<release-notes-8.18.1, {elastic-sec} version 8.18.1>>
 * <<release-notes-8.18.0, {elastic-sec} version 8.18.0>>
 * <<release-notes-8.17.5, {elastic-sec} version 8.17.5>>
 * <<release-notes-8.17.4, {elastic-sec} version 8.17.4>>

docs/release-notes/8.18.asciidoc

@@ -1,6 +1,38 @@
 [[release-notes-header-8.18.0]]
 == 8.18
 
+[discrete]
+[[release-notes-8.18.1]]
+=== 8.18.1
+
+// tag::known-issue[]
+[discrete]
+.The technical preview badge incorrectly displays on the alert suppression fields for event correlation rules 
+[%collapsible]
+====
+*Details* +
+On April 8, 2025, it was discovered that alert suppression for event correlation rules is incorrectly shown as being in technical preview when you create a new rule. For more information, check https://github.com/elastic/docs-content/issues/1021[#1021].
+
+====
+// end::known-issue[]
+
+[discrete]
+[[enhancements-8.18.1]]
+==== Enhancements
+* Updates the **MITRE ATT&CK® coverage** page mapping to `v16.1` ({kibana-pull}215026[#215026]).
+* Adds a background task to upgrade Agentless deployments after {kib} has been upgraded ({kibana-pull}207143[#207143]).
+* Improves {elastic-defend}'s' CPU usage on systems with very high event volumes.
+
+[discrete]
+[[bug-fixes-8.18.1]]
+==== Fixes
+* Removes the check for unused connector roles ({kibana-pull}219358[#219358]).
+* Simplifies and improves the rule import error message ({kibana-pull}218701[#218701]).
+* Fixes the related integrations render performance on rule editing pages ({kibana-pull}217254[#217254]).
+* Prevents {esql} rules from timing out if the rule query takes longer than five minutes to complete ({kibana-pull}216667[#216667]).
+* Improves {elastic-defend}'s call site analysis logic.
+* Fixes a bug in {elastic-defend}'s redaction of diagnostics bundles.
+
 [discrete]
 [[release-notes-8.18.0]]
 === 8.18.0
@@ -29,7 +61,7 @@ Duplicate your rules and enable them.
 [%collapsible]
 ====
 *Details* +
-On April 8, 2025, it was discovered that alert suppression for event correlation rules is incorrectly shown as being in technical preview when you create a new rule. For more information, check (https://github.com/elastic/docs-content/issues/1021)[#1021].
+On April 8, 2025, it was discovered that alert suppression for event correlation rules is incorrectly shown as being in technical preview when you create a new rule. For more information, check https://github.com/elastic/docs-content/issues/1021[#1021].
 
 ====
 // end::known-issue[]
@@ -44,6 +76,10 @@ When you install an {elastic-defend} integration or a new agent policy for this
 
 *Workaround* +
 To resolve this issue, before you add an {elastic-defend} integration to a policy in {fleet}, apply any pending prebuilt rule updates. This will prevent rule actions, exceptions, and customizations from being overwritten.
+
+*Resolved* +
+This issue is fixed in {stack} versions 8.17.6, 8.18.1, and 9.0.1.
+
 ====
 // end::known-issue[]