diff --git a/package.json b/package.json
index 4fe6357e67f50..acdd3bca05602 100644
--- a/package.json
+++ b/package.json
@@ -121,7 +121,7 @@
     "@elastic/ecs": "^8.11.5",
     "@elastic/elasticsearch": "9.0.0-alpha.3",
     "@elastic/ems-client": "8.6.3",
-    "@elastic/eui": "99.3.0-borealis.0",
+    "@elastic/eui": "99.4.0-borealis.0",
     "@elastic/eui-theme-borealis": "0.0.11",
     "@elastic/filesaver": "1.1.2",
     "@elastic/node-crypto": "^1.2.3",
diff --git a/src/core/packages/chrome/browser-internal/src/ui/header/__snapshots__/collapsible_nav.test.tsx.snap b/src/core/packages/chrome/browser-internal/src/ui/header/__snapshots__/collapsible_nav.test.tsx.snap
index d8f83640c5d61..23a53cfd8df28 100644
--- a/src/core/packages/chrome/browser-internal/src/ui/header/__snapshots__/collapsible_nav.test.tsx.snap
+++ b/src/core/packages/chrome/browser-internal/src/ui/header/__snapshots__/collapsible_nav.test.tsx.snap
@@ -140,6 +140,7 @@ Array [
         <button
           aria-controls="generated-id"
           aria-expanded="true"
+          aria-hidden="true"
           aria-labelledby="generated-id"
           class="euiButtonIcon euiAccordion__arrow emotion-euiButtonIcon-xs-empty-text-euiAccordion__arrow-right-isOpen"
           tabindex="-1"
@@ -263,6 +264,7 @@ Array [
           <button
             aria-controls="generated-id"
             aria-expanded="true"
+            aria-hidden="true"
             aria-labelledby="generated-id"
             class="euiButtonIcon euiAccordion__arrow emotion-euiButtonIcon-xs-empty-text-euiAccordion__arrow-right-isOpen"
             tabindex="-1"
@@ -393,6 +395,7 @@ Array [
           <button
             aria-controls="generated-id"
             aria-expanded="true"
+            aria-hidden="true"
             aria-labelledby="generated-id"
             class="euiButtonIcon euiAccordion__arrow emotion-euiButtonIcon-xs-empty-text-euiAccordion__arrow-right-isOpen"
             tabindex="-1"
@@ -506,6 +509,7 @@ Array [
           <button
             aria-controls="generated-id"
             aria-expanded="true"
+            aria-hidden="true"
             aria-labelledby="generated-id"
             class="euiButtonIcon euiAccordion__arrow emotion-euiButtonIcon-xs-empty-text-euiAccordion__arrow-right-isOpen"
             tabindex="-1"
@@ -602,6 +606,7 @@ Array [
           <button
             aria-controls="generated-id"
             aria-expanded="true"
+            aria-hidden="true"
             aria-labelledby="generated-id"
             class="euiButtonIcon euiAccordion__arrow emotion-euiButtonIcon-xs-empty-text-euiAccordion__arrow-right-isOpen"
             tabindex="-1"
diff --git a/src/dev/license_checker/config.ts b/src/dev/license_checker/config.ts
index e7fa8ba1167e8..0b0962d1e5069 100644
--- a/src/dev/license_checker/config.ts
+++ b/src/dev/license_checker/config.ts
@@ -87,7 +87,7 @@ export const LICENSE_OVERRIDES = {
   'jsts@1.6.2': ['Eclipse Distribution License - v 1.0'], // cf. https://github.com/bjornharrtell/jsts
   '@mapbox/jsonlint-lines-primitives@2.0.2': ['MIT'], // license in readme https://github.com/tmcw/jsonlint
   '@elastic/ems-client@8.6.3': ['Elastic License 2.0'],
-  '@elastic/eui@99.3.0-borealis.0': ['Elastic License 2.0 OR AGPL-3.0-only OR SSPL-1.0'],
+  '@elastic/eui@99.4.0-borealis.0': ['Elastic License 2.0 OR AGPL-3.0-only OR SSPL-1.0'],
   '@elastic/eui-theme-borealis@0.0.11': ['Elastic License 2.0 OR AGPL-3.0-only OR SSPL-1.0'],
   'language-subtag-registry@0.3.21': ['CC-BY-4.0'], // retired ODC‑By license https://github.com/mattcg/language-subtag-registry
   'buffers@0.1.1': ['MIT'], // license in importing module https://www.npmjs.com/package/binary
diff --git a/src/platform/packages/private/kbn-reporting/public/share/share_context_menu/__snapshots__/screen_capture_panel_content.test.tsx.snap b/src/platform/packages/private/kbn-reporting/public/share/share_context_menu/__snapshots__/screen_capture_panel_content.test.tsx.snap
index 4060d535bc875..5fbc5bf09c016 100644
--- a/src/platform/packages/private/kbn-reporting/public/share/share_context_menu/__snapshots__/screen_capture_panel_content.test.tsx.snap
+++ b/src/platform/packages/private/kbn-reporting/public/share/share_context_menu/__snapshots__/screen_capture_panel_content.test.tsx.snap
@@ -93,6 +93,7 @@ exports[`ScreenCapturePanelContent properly renders a view with "canvas" layout
       <button
         aria-controls="advanced-options"
         aria-expanded="false"
+        aria-hidden="true"
         aria-labelledby="generated-id"
         class="euiButtonIcon euiAccordion__arrow emotion-euiButtonIcon-xs-empty-text-euiAccordion__arrow-left-isClosed"
         tabindex="-1"
@@ -275,6 +276,7 @@ exports[`ScreenCapturePanelContent properly renders a view with "print" layout o
       <button
         aria-controls="advanced-options"
         aria-expanded="false"
+        aria-hidden="true"
         aria-labelledby="generated-id"
         class="euiButtonIcon euiAccordion__arrow emotion-euiButtonIcon-xs-empty-text-euiAccordion__arrow-left-isClosed"
         tabindex="-1"
@@ -404,6 +406,7 @@ exports[`ScreenCapturePanelContent renders the default view properly 1`] = `
       <button
         aria-controls="advanced-options"
         aria-expanded="false"
+        aria-hidden="true"
         aria-labelledby="generated-id"
         class="euiButtonIcon euiAccordion__arrow emotion-euiButtonIcon-xs-empty-text-euiAccordion__arrow-left-isClosed"
         tabindex="-1"
diff --git a/src/platform/packages/shared/shared-ux/chrome/navigation/src/ui/components/navigation_section_ui.tsx b/src/platform/packages/shared/shared-ux/chrome/navigation/src/ui/components/navigation_section_ui.tsx
index 6235d30bcf0a9..596327f8e4c55 100644
--- a/src/platform/packages/shared/shared-ux/chrome/navigation/src/ui/components/navigation_section_ui.tsx
+++ b/src/platform/packages/shared/shared-ux/chrome/navigation/src/ui/components/navigation_section_ui.tsx
@@ -532,7 +532,9 @@ export const NavigationSectionUI: FC<Props> = React.memo(({ navNode: _navNode })
   }, [topLevelItems, serializeAccordionItems]);
 
   if (!isEuiCollapsibleNavItemProps(props)) {
-    throw new Error(`Invalid EuiCollapsibleNavItem props for node ${props.id}`);
+    throw new Error(
+      `Invalid EuiCollapsibleNavItem props for node ${(props as EuiCollapsibleNavSubItemProps).id}`
+    );
   }
 
   if (!isVisible) {
diff --git a/x-pack/solutions/security/packages/kbn-securitysolution-autocomplete/src/es_field_selector/__tests__/__snapshots__/index.test.tsx.snap b/x-pack/solutions/security/packages/kbn-securitysolution-autocomplete/src/es_field_selector/__tests__/__snapshots__/index.test.tsx.snap
index 4ab1374ec2565..ee0b345d06a26 100644
--- a/x-pack/solutions/security/packages/kbn-securitysolution-autocomplete/src/es_field_selector/__tests__/__snapshots__/index.test.tsx.snap
+++ b/x-pack/solutions/security/packages/kbn-securitysolution-autocomplete/src/es_field_selector/__tests__/__snapshots__/index.test.tsx.snap
@@ -25,6 +25,7 @@ exports[`FieldComponent should allow user to clear values if isClearable is true
               aria-autocomplete="list"
               aria-controls=""
               aria-expanded="false"
+              aria-haspopup="listbox"
               aria-invalid="false"
               autocomplete="off"
               class="euiComboBox__input emotion-euiComboBoxInput"
@@ -94,6 +95,7 @@ exports[`FieldComponent should render the component disabled if isDisabled is tr
               aria-autocomplete="list"
               aria-controls=""
               aria-expanded="false"
+              aria-haspopup="listbox"
               aria-invalid="false"
               autocomplete="off"
               class="euiComboBox__input emotion-euiComboBoxInput"
@@ -137,6 +139,7 @@ exports[`FieldComponent should render the component enabled and displays the sel
               aria-autocomplete="list"
               aria-controls=""
               aria-expanded="false"
+              aria-haspopup="listbox"
               aria-invalid="false"
               autocomplete="off"
               class="euiComboBox__input emotion-euiComboBoxInput"
@@ -196,6 +199,7 @@ exports[`FieldComponent should render the loading spinner if isLoading is true w
               aria-autocomplete="list"
               aria-controls=""
               aria-expanded="false"
+              aria-haspopup="listbox"
               aria-invalid="false"
               autocomplete="off"
               class="euiComboBox__input emotion-euiComboBoxInput"
diff --git a/x-pack/solutions/security/plugins/cloud_defend/public/components/control_general_view_selector/index.test.tsx b/x-pack/solutions/security/plugins/cloud_defend/public/components/control_general_view_selector/index.test.tsx
index c82d7b479ce96..d3ad428971bf3 100644
--- a/x-pack/solutions/security/plugins/cloud_defend/public/components/control_general_view_selector/index.test.tsx
+++ b/x-pack/solutions/security/plugins/cloud_defend/public/components/control_general_view_selector/index.test.tsx
@@ -667,12 +667,11 @@ describe('<ControlGeneralViewSelector />', () => {
     const selector = getByTestId('cloud-defend-selector');
 
     // should start as closed.
-    // there are two mock selectors, and the last one will auto open
     expect(
       await within(selector).findAllByRole('button', {
         expanded: false,
       })
-    ).toHaveLength(2);
+    ).toHaveLength(1);
     expect(
       within(selector).queryByRole('button', {
         expanded: true,
@@ -696,7 +695,7 @@ describe('<ControlGeneralViewSelector />', () => {
       await within(selector).findAllByRole('button', {
         expanded: true,
       })
-    ).toHaveLength(2);
+    ).toHaveLength(1);
 
     expect(queryByTestId('cloud-defend-conditions-count')).not.toBeInTheDocument();
   });
diff --git a/yarn.lock b/yarn.lock
index 8bef78364d3e0..75f2cabef2042 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2292,10 +2292,10 @@
     chroma-js "^2.4.2"
     lodash "^4.17.21"
 
-"@elastic/eui@99.3.0-borealis.0":
-  version "99.3.0-borealis.0"
-  resolved "https://registry.yarnpkg.com/@elastic/eui/-/eui-99.3.0-borealis.0.tgz#e8c26a9d160783682bcdeea65846d8295e7cd391"
-  integrity sha512-T88s2vQHEHy6g/mA8K2cDr3IUKFGZcdNHFIRUqJwYjBW6JwHyLkrFZuFweK88IyJv1F8vsTv1RlCeeta/AZlLA==
+"@elastic/eui@99.4.0-borealis.0":
+  version "99.4.0-borealis.0"
+  resolved "https://registry.yarnpkg.com/@elastic/eui/-/eui-99.4.0-borealis.0.tgz#8637698371fa3c6827da4f7cb689d3cd39de3841"
+  integrity sha512-ws2OVe67WrO9CBkembcqBXFh3Lo10HRvk19MZZL22RoZ3dyGlNr0WTxvZpLPEykycOaOCnf3hAo9p8V16wPWvw==
   dependencies:
     "@elastic/eui-theme-common" "0.0.10"
     "@elastic/prismjs-esql" "^1.0.0"