diff --git a/CHANGELOG.md b/CHANGELOG.md
index 021ea178c0..ff5da43478 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -387,6 +387,7 @@ Breaking changes in this release:
    - Added `img-src data:`, required for icons
 - Downgraded graph upsert conflict checks, by [@compulim](https://github.com/compulim) in PR [#5674](https://github.com/microsoft/BotFramework-WebChat/pull/5674)
 - Fixed virtual keyboard should show up on tap after being suppressed, in iOS 26.2, by [@compulim](https://github.com/compulim) in PR [#5678](https://github.com/microsoft/BotFramework-WebChat/pull/5678)
+- Fixed compatibility with `create-react-app` by adding file extension to `core-js` imports, by [@compulim](https://github.com/compulim) in PR [#5680](https://github.com/microsoft/BotFramework-WebChat/pull/5680)
 
 ## [4.18.0] - 2024-07-10
 
diff --git a/packages/core-graph/src/private/SlantGraph/private/autoInversion.ts b/packages/core-graph/src/private/SlantGraph/private/autoInversion.ts
index d35dd1b5bd..3d3e088e30 100644
--- a/packages/core-graph/src/private/SlantGraph/private/autoInversion.ts
+++ b/packages/core-graph/src/private/SlantGraph/private/autoInversion.ts
@@ -1,5 +1,5 @@
 // @ts-expect-error No @types/core-js-pure.
-import difference from 'core-js-pure/features/set/difference';
+import difference from 'core-js-pure/features/set/difference.js';
 import { type GraphMiddleware } from '../../Graph';
 import { type SlantNode } from '../../schemas/colorNode';
 import type { Identifier } from '../../schemas/Identifier';
diff --git a/packages/core/src/reducers/activities/sort/private/insertSorted.ts b/packages/core/src/reducers/activities/sort/private/insertSorted.ts
index a2e663c4df..766554a600 100644
--- a/packages/core/src/reducers/activities/sort/private/insertSorted.ts
+++ b/packages/core/src/reducers/activities/sort/private/insertSorted.ts
@@ -1,5 +1,5 @@
 // @ts-ignore No @types/core-js-pure
-import { default as toSpliced_ } from 'core-js-pure/features/array/to-spliced';
+import { default as toSpliced_ } from 'core-js-pure/features/array/to-spliced.js';
 
 // The Node.js version we are using for CI/CD does not support Array.prototype.toSpliced yet.
 function toSpliced<T>(array: readonly T[], start: number, deleteCount: number, ...items: T[]): T[] {