diff --git a/native/input/input-state-container.react.js b/native/input/input-state-container.react.js
--- a/native/input/input-state-container.react.js
+++ b/native/input/input-state-container.react.js
@@ -19,6 +19,7 @@
   updateMultimediaMessageMediaActionType,
   useBlobServiceUpload,
 } from 'lib/actions/upload-actions.js';
+import { useInvalidCSATLogOut } from 'lib/actions/user-actions.js';
 import {
   type SendMultimediaMessagePayload,
   useInputStateContainerSendMultimediaMessage,
@@ -158,6 +159,7 @@
   ) => Promise<NewThreadResult>,
   +newThickThread: (request: NewThickThreadRequest) => Promise<string>,
   +textMessageCreationSideEffectsFunc: CreationSideEffectsFunc<RawTextMessageInfo>,
+  +invalidTokenLogOut: () => Promise<void>,
 };
 type State = {
   +pendingUploads: PendingMultimediaUploads,
@@ -915,6 +917,10 @@
       mediaMissionResult = { success: true };
     } catch (e) {
       uploadExceptionMessage = getMessageForException(e);
+      if (uploadExceptionMessage === 'invalid_csat') {
+        void this.props.invalidTokenLogOut();
+        return undefined;
+      }
       onUploadFailed('upload failed');
       mediaMissionResult = {
         success: false,
@@ -1709,6 +1715,7 @@
     const staffCanSee = useStaffCanSee();
     const textMessageCreationSideEffectsFunc =
       useMessageCreationSideEffectsFunc<RawTextMessageInfo>(messageTypes.TEXT);
+    const callInvalidTokenLogOut = useInvalidCSATLogOut();
 
     return (
       <InputStateContainer
@@ -1728,6 +1735,7 @@
         dispatch={dispatch}
         staffCanSee={staffCanSee}
         textMessageCreationSideEffectsFunc={textMessageCreationSideEffectsFunc}
+        invalidTokenLogOut={callInvalidTokenLogOut}
       />
     );
   });
diff --git a/web/input/input-state-container.react.js b/web/input/input-state-container.react.js
--- a/web/input/input-state-container.react.js
+++ b/web/input/input-state-container.react.js
@@ -24,6 +24,7 @@
   useBlobServiceUpload,
   useDeleteUpload,
 } from 'lib/actions/upload-actions.js';
+import { useInvalidCSATLogOut } from 'lib/actions/user-actions.js';
 import {
   type PushModal,
   useModalContext,
@@ -157,6 +158,7 @@
   +unregisterSendCallback: (() => mixed) => void,
   +textMessageCreationSideEffectsFunc: CreationSideEffectsFunc<RawTextMessageInfo>,
   +identityContext: ?IdentityClientContextType,
+  +invalidTokenLogOut: () => Promise<void>,
 };
 type WritableState = {
   pendingUploads: {
@@ -931,6 +933,10 @@
       });
     } catch (e) {
       uploadExceptionMessage = getMessageForException(e);
+      if (uploadExceptionMessage === 'invalid_csat') {
+        void this.props.invalidTokenLogOut();
+        return;
+      }
       this.handleUploadFailure(threadID, localID);
     }
     userTime = Date.now() - selectTime;
@@ -1203,7 +1209,7 @@
             });
           }
           if (isBlobServiceURI(pendingUpload.uri)) {
-            const identityContext = this.props.identityContext;
+            const { invalidTokenLogOut, identityContext } = this.props;
             invariant(identityContext, 'Identity context should be set');
             invariant(
               pendingUpload.blobHolder,
@@ -1215,7 +1221,13 @@
               const authMetadata = await identityContext.getAuthMetadata();
               const defaultHeaders =
                 createDefaultHTTPRequestHeaders(authMetadata);
-              await removeBlobHolder({ blobHash, holder }, defaultHeaders);
+              const result = await removeBlobHolder(
+                { blobHash, holder },
+                defaultHeaders,
+              );
+              if (!result.success && result.reason === 'INVALID_CSAT') {
+                void invalidTokenLogOut();
+              }
             })();
           }
         }
@@ -1664,6 +1676,7 @@
     const dispatchActionPromise = useDispatchActionPromise();
     const modalContext = useModalContext();
     const identityContext = React.useContext(IdentityClientContext);
+    const callInvalidTokenLogOut = useInvalidCSATLogOut();
 
     const [sendCallbacks, setSendCallbacks] = React.useState<
       $ReadOnlyArray<() => mixed>,
@@ -1705,6 +1718,7 @@
         unregisterSendCallback={unregisterSendCallback}
         textMessageCreationSideEffectsFunc={textMessageCreationSideEffectsFunc}
         identityContext={identityContext}
+        invalidTokenLogOut={callInvalidTokenLogOut}
       />
     );
   });