diff --git a/packages/server/src/utils/buildChatflow.ts b/packages/server/src/utils/buildChatflow.ts
index 90297076f..3257f0a8a 100644
--- a/packages/server/src/utils/buildChatflow.ts
+++ b/packages/server/src/utils/buildChatflow.ts
@@ -184,6 +184,9 @@ export const utilBuildChatflow = async (req: Request, isInternal: boolean = fals
 
                 fs.unlinkSync(file.path)
             }
+            if (overrideConfig.vars && typeof overrideConfig.vars === 'string') {
+                overrideConfig.vars = JSON.parse(overrideConfig.vars)
+            }
             incomingInput = {
                 question: req.body.question ?? 'hello',
                 overrideConfig
diff --git a/packages/server/src/utils/upsertVector.ts b/packages/server/src/utils/upsertVector.ts
index 044716e74..c0e5e4d98 100644
--- a/packages/server/src/utils/upsertVector.ts
+++ b/packages/server/src/utils/upsertVector.ts
@@ -89,6 +89,9 @@ export const upsertVector = async (req: Request, isInternal: boolean = false) =>
 
                 fs.unlinkSync(file.path)
             }
+            if (overrideConfig.vars && typeof overrideConfig.vars === 'string') {
+                overrideConfig.vars = JSON.parse(overrideConfig.vars)
+            }
             incomingInput = {
                 question: req.body.question ?? 'hello',
                 overrideConfig,