diff --git a/package.json b/package.json
index 669c20277..aa2e0a6c6 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "hono",
-  "version": "4.6.13",
+  "version": "4.6.14",
   "description": "Web framework built on Web Standards",
   "main": "dist/cjs/index.js",
   "type": "module",
diff --git a/runtime-tests/lambda/index.test.ts b/runtime-tests/lambda/index.test.ts
index e5b06de19..adf9fc835 100644
--- a/runtime-tests/lambda/index.test.ts
+++ b/runtime-tests/lambda/index.test.ts
@@ -537,7 +537,7 @@ describe('AWS Lambda Adapter for Hono', () => {
         expect(albResponse.statusCode).toBe(200)
         expect(albResponse.headers).toEqual(
           expect.objectContaining({
-            'content-type': 'application/json; charset=UTF-8',
+            'content-type': 'application/json',
           })
         )
       })
@@ -598,7 +598,7 @@ describe('AWS Lambda Adapter for Hono', () => {
         expect(albResponse.multiValueHeaders).toBeDefined()
         expect(albResponse.multiValueHeaders).toEqual(
           expect.objectContaining({
-            'content-type': ['application/json; charset=UTF-8'],
+            'content-type': ['application/json'],
           })
         )
       })
diff --git a/src/adapter/aws-lambda/handler.test.ts b/src/adapter/aws-lambda/handler.test.ts
index 1d4358aec..97c7da4c1 100644
--- a/src/adapter/aws-lambda/handler.test.ts
+++ b/src/adapter/aws-lambda/handler.test.ts
@@ -13,7 +13,7 @@ describe('isContentTypeBinary', () => {
     expect(isContentTypeBinary('text/javascript')).toBe(false)
     expect(isContentTypeBinary('application/json')).toBe(false)
     expect(isContentTypeBinary('application/ld+json')).toBe(false)
-    expect(isContentTypeBinary('application/json; charset=UTF-8')).toBe(false)
+    expect(isContentTypeBinary('application/json')).toBe(false)
   })
 })
 
diff --git a/src/adapter/lambda-edge/handler.test.ts b/src/adapter/lambda-edge/handler.test.ts
index aa17c904a..d9bbba863 100644
--- a/src/adapter/lambda-edge/handler.test.ts
+++ b/src/adapter/lambda-edge/handler.test.ts
@@ -13,7 +13,7 @@ describe('isContentTypeBinary', () => {
     expect(isContentTypeBinary('text/javascript')).toBe(false)
     expect(isContentTypeBinary('application/json')).toBe(false)
     expect(isContentTypeBinary('application/ld+json')).toBe(false)
-    expect(isContentTypeBinary('application/json; charset=UTF-8')).toBe(false)
+    expect(isContentTypeBinary('application/json')).toBe(false)
   })
 })
 
diff --git a/src/context.test.ts b/src/context.test.ts
index 622852604..8230a9548 100644
--- a/src/context.test.ts
+++ b/src/context.test.ts
@@ -51,7 +51,7 @@ describe('Context', () => {
   it('c.json()', async () => {
     const res = c.json({ message: 'Hello' }, 201, { 'X-Custom': 'Message' })
     expect(res.status).toBe(201)
-    expect(res.headers.get('Content-Type')).toMatch('application/json; charset=UTF-8')
+    expect(res.headers.get('Content-Type')).toMatch('application/json')
     const text = await res.text()
     expect(text).toBe('{"message":"Hello"}')
     expect(res.headers.get('X-Custom')).toBe('Message')
@@ -182,7 +182,7 @@ describe('Context', () => {
     c.status(404)
     const res = c.json({ hono: 'great app' })
     expect(res.status).toBe(404)
-    expect(res.headers.get('Content-Type')).toMatch('application/json; charset=UTF-8')
+    expect(res.headers.get('Content-Type')).toMatch('application/json')
     const obj: { [key: string]: string } = await res.json()
     expect(obj['hono']).toBe('great app')
   })
diff --git a/src/context.ts b/src/context.ts
index 86124e008..8447f2128 100644
--- a/src/context.ts
+++ b/src/context.ts
@@ -777,7 +777,7 @@ export class Context<
   ): JSONRespondReturn<T, U> => {
     const body = JSON.stringify(object)
     this.#preparedHeaders ??= {}
-    this.#preparedHeaders['content-type'] = 'application/json; charset=UTF-8'
+    this.#preparedHeaders['content-type'] = 'application/json'
     /* eslint-disable @typescript-eslint/no-explicit-any */
     return (
       typeof arg === 'number' ? this.#newResponse(body, arg, headers) : this.#newResponse(body, arg)
diff --git a/src/helper/streaming/stream.test.ts b/src/helper/streaming/stream.test.ts
index 820579de5..4a9eff2ed 100644
--- a/src/helper/streaming/stream.test.ts
+++ b/src/helper/streaming/stream.test.ts
@@ -71,6 +71,28 @@ describe('Basic Streaming Helper', () => {
     expect(aborted).toBeTruthy()
   })
 
+  it('Check stream Response if pipe is aborted by abort signal', async () => {
+    const ac = new AbortController()
+    const req = new Request('http://localhost/', { signal: ac.signal })
+    const c = new Context(req)
+
+    let aborted = false
+    const res = stream(c, async (stream) => {
+      stream.onAbort(() => {
+        aborted = true
+      })
+      await stream.pipe(new ReadableStream())
+    })
+    if (!res.body) {
+      throw new Error('Body is null')
+    }
+    const reader = res.body.getReader()
+    const pReading = reader.read()
+    ac.abort()
+    await pReading
+    expect(aborted).toBeTruthy()
+  })
+
   it('Check stream Response if error occurred', async () => {
     const onError = vi.fn()
     const res = stream(
diff --git a/src/helper/streaming/stream.ts b/src/helper/streaming/stream.ts
index 3d0449573..5878c2188 100644
--- a/src/helper/streaming/stream.ts
+++ b/src/helper/streaming/stream.ts
@@ -22,7 +22,11 @@ export const stream = (
     try {
       await cb(stream)
     } catch (e) {
-      if (e instanceof Error && onError) {
+      if (e === undefined) {
+        // If reading is canceled without a reason value (e.g. by StreamingApi)
+        // then the .pipeTo() promise will reject with undefined.
+        // In this case, do nothing because the stream is already closed.
+      } else if (e instanceof Error && onError) {
         await onError(e, stream)
       } else {
         console.error(e)
diff --git a/src/middleware/basic-auth/index.test.ts b/src/middleware/basic-auth/index.test.ts
index e64d2db59..c4065e60e 100644
--- a/src/middleware/basic-auth/index.test.ts
+++ b/src/middleware/basic-auth/index.test.ts
@@ -295,7 +295,7 @@ describe('Basic Auth by Middleware', () => {
     const res = await app.request(req)
     expect(res).not.toBeNull()
     expect(res.status).toBe(401)
-    expect(res.headers.get('Content-Type')).toMatch('application/json; charset=UTF-8')
+    expect(res.headers.get('Content-Type')).toMatch('application/json')
     expect(handlerExecuted).toBeFalsy()
     expect(await res.text()).toBe('{"message":"Custom unauthorized message as object"}')
   })
@@ -314,7 +314,7 @@ describe('Basic Auth by Middleware', () => {
     const res = await app.request(req)
     expect(res).not.toBeNull()
     expect(res.status).toBe(401)
-    expect(res.headers.get('Content-Type')).toMatch('application/json; charset=UTF-8')
+    expect(res.headers.get('Content-Type')).toMatch('application/json')
     expect(handlerExecuted).toBeFalsy()
     expect(await res.text()).toBe('{"message":"Custom unauthorized message as function object"}')
   })
diff --git a/src/middleware/basic-auth/index.ts b/src/middleware/basic-auth/index.ts
index aa4ca72d0..45d5f6c65 100644
--- a/src/middleware/basic-auth/index.ts
+++ b/src/middleware/basic-auth/index.ts
@@ -120,7 +120,7 @@ export const basicAuth = (
             status,
             headers: {
               ...headers,
-              'content-type': 'application/json; charset=UTF-8',
+              'content-type': 'application/json',
             },
           })
     throw new HTTPException(status, { res })
diff --git a/src/middleware/bearer-auth/index.test.ts b/src/middleware/bearer-auth/index.test.ts
index 4dca87f22..2b559c021 100644
--- a/src/middleware/bearer-auth/index.test.ts
+++ b/src/middleware/bearer-auth/index.test.ts
@@ -400,7 +400,7 @@ describe('Bearer Auth by Middleware', () => {
     const res = await app.request(req)
     expect(res).not.toBeNull()
     expect(res.status).toBe(401)
-    expect(res.headers.get('Content-Type')).toMatch('application/json; charset=UTF-8')
+    expect(res.headers.get('Content-Type')).toMatch('application/json')
     expect(handlerExecuted).toBeFalsy()
     expect(await res.text()).toBe('{"message":"Custom no authentication header message as object"}')
   })
@@ -423,7 +423,7 @@ describe('Bearer Auth by Middleware', () => {
     const res = await app.request(req)
     expect(res).not.toBeNull()
     expect(res.status).toBe(401)
-    expect(res.headers.get('Content-Type')).toMatch('application/json; charset=UTF-8')
+    expect(res.headers.get('Content-Type')).toMatch('application/json')
     expect(handlerExecuted).toBeFalsy()
     expect(await res.text()).toBe(
       '{"message":"Custom no authentication header message as function object"}'
@@ -450,7 +450,7 @@ describe('Bearer Auth by Middleware', () => {
     const res = await app.request(req)
     expect(res).not.toBeNull()
     expect(res.status).toBe(400)
-    expect(res.headers.get('Content-Type')).toMatch('application/json; charset=UTF-8')
+    expect(res.headers.get('Content-Type')).toMatch('application/json')
     expect(handlerExecuted).toBeFalsy()
     expect(await res.text()).toBe(
       '{"message":"Custom invalid authentication header message as object"}'
@@ -477,7 +477,7 @@ describe('Bearer Auth by Middleware', () => {
     const res = await app.request(req)
     expect(res).not.toBeNull()
     expect(res.status).toBe(400)
-    expect(res.headers.get('Content-Type')).toMatch('application/json; charset=UTF-8')
+    expect(res.headers.get('Content-Type')).toMatch('application/json')
     expect(handlerExecuted).toBeFalsy()
     expect(await res.text()).toBe(
       '{"message":"Custom invalid authentication header message as function object"}'
@@ -500,7 +500,7 @@ describe('Bearer Auth by Middleware', () => {
     const res = await app.request(req)
     expect(res).not.toBeNull()
     expect(res.status).toBe(401)
-    expect(res.headers.get('Content-Type')).toMatch('application/json; charset=UTF-8')
+    expect(res.headers.get('Content-Type')).toMatch('application/json')
     expect(handlerExecuted).toBeFalsy()
     expect(await res.text()).toBe('{"message":"Custom invalid token message as object"}')
   })
@@ -521,7 +521,7 @@ describe('Bearer Auth by Middleware', () => {
     const res = await app.request(req)
     expect(res).not.toBeNull()
     expect(res.status).toBe(401)
-    expect(res.headers.get('Content-Type')).toMatch('application/json; charset=UTF-8')
+    expect(res.headers.get('Content-Type')).toMatch('application/json')
     expect(handlerExecuted).toBeFalsy()
     expect(await res.text()).toBe('{"message":"Custom invalid token message as function object"}')
   })
diff --git a/src/middleware/bearer-auth/index.ts b/src/middleware/bearer-auth/index.ts
index 0e86d4d47..7a83345f4 100644
--- a/src/middleware/bearer-auth/index.ts
+++ b/src/middleware/bearer-auth/index.ts
@@ -103,7 +103,7 @@ export const bearerAuth = (options: BearerAuthOptions): MiddlewareHandler => {
             status,
             headers: {
               ...headers,
-              'content-type': 'application/json; charset=UTF-8',
+              'content-type': 'application/json',
             },
           })
     throw new HTTPException(status, { res })
diff --git a/src/router/pattern-router/router.ts b/src/router/pattern-router/router.ts
index d15610409..5f599471e 100644
--- a/src/router/pattern-router/router.ts
+++ b/src/router/pattern-router/router.ts
@@ -3,6 +3,8 @@ import { METHOD_NAME_ALL, UnsupportedPathError } from '../../router'
 
 type Route<T> = [RegExp, string, T] // [pattern, method, handler, path]
 
+const emptyParams = Object.create(null)
+
 export class PatternRouter<T> implements Router<T> {
   name: string = 'PatternRouter'
   #routes: Route<T>[] = []
@@ -46,7 +48,7 @@ export class PatternRouter<T> implements Router<T> {
       if (routeMethod === method || routeMethod === METHOD_NAME_ALL) {
         const match = pattern.exec(path)
         if (match) {
-          handlers.push([handler, match.groups || Object.create(null)])
+          handlers.push([handler, match.groups || emptyParams])
         }
       }
     }
diff --git a/src/router/trie-router/node.ts b/src/router/trie-router/node.ts
index 94ab4de19..b19f8cff3 100644
--- a/src/router/trie-router/node.ts
+++ b/src/router/trie-router/node.ts
@@ -13,13 +13,15 @@ type HandlerParamsSet<T> = HandlerSet<T> & {
   params: Record<string, string>
 }
 
+const emptyParams = Object.create(null)
+
 export class Node<T> {
   #methods: Record<string, HandlerSet<T>>[]
 
   #children: Record<string, Node<T>>
   #patterns: Pattern[]
   #order: number = 0
-  #params: Record<string, string> = Object.create(null)
+  #params: Record<string, string> = emptyParams
 
   constructor(method?: string, handler?: T, children?: Record<string, Node<T>>) {
     this.#children = children || Object.create(null)
@@ -82,7 +84,7 @@ export class Node<T> {
     node: Node<T>,
     method: string,
     nodeParams: Record<string, string>,
-    params: Record<string, string>
+    params?: Record<string, string>
   ): HandlerParamsSet<T>[] {
     const handlerSets: HandlerParamsSet<T>[] = []
     for (let i = 0, len = node.#methods.length; i < len; i++) {
@@ -91,15 +93,16 @@ export class Node<T> {
       const processedSet: Record<number, boolean> = {}
       if (handlerSet !== undefined) {
         handlerSet.params = Object.create(null)
-        for (let i = 0, len = handlerSet.possibleKeys.length; i < len; i++) {
-          const key = handlerSet.possibleKeys[i]
-          const processed = processedSet[handlerSet.score]
-          handlerSet.params[key] =
-            params[key] && !processed ? params[key] : nodeParams[key] ?? params[key]
-          processedSet[handlerSet.score] = true
-        }
-
         handlerSets.push(handlerSet)
+        if (nodeParams !== emptyParams || (params && params !== emptyParams)) {
+          for (let i = 0, len = handlerSet.possibleKeys.length; i < len; i++) {
+            const key = handlerSet.possibleKeys[i]
+            const processed = processedSet[handlerSet.score]
+            handlerSet.params[key] =
+              params?.[key] && !processed ? params[key] : nodeParams[key] ?? params?.[key]
+            processedSet[handlerSet.score] = true
+          }
+        }
       }
     }
     return handlerSets
@@ -107,7 +110,7 @@ export class Node<T> {
 
   search(method: string, path: string): [[T, Params][]] {
     const handlerSets: HandlerParamsSet<T>[] = []
-    this.#params = Object.create(null)
+    this.#params = emptyParams
 
     // eslint-disable-next-line @typescript-eslint/no-this-alias
     const curNode: Node<T> = this
@@ -129,17 +132,10 @@ export class Node<T> {
             // '/hello/*' => match '/hello'
             if (nextNode.#children['*']) {
               handlerSets.push(
-                ...this.#getHandlerSets(
-                  nextNode.#children['*'],
-                  method,
-                  node.#params,
-                  Object.create(null)
-                )
+                ...this.#getHandlerSets(nextNode.#children['*'], method, node.#params)
               )
             }
-            handlerSets.push(
-              ...this.#getHandlerSets(nextNode, method, node.#params, Object.create(null))
-            )
+            handlerSets.push(...this.#getHandlerSets(nextNode, method, node.#params))
           } else {
             tempNodes.push(nextNode)
           }
@@ -147,17 +143,14 @@ export class Node<T> {
 
         for (let k = 0, len3 = node.#patterns.length; k < len3; k++) {
           const pattern = node.#patterns[k]
-
-          const params = { ...node.#params }
+          const params = node.#params === emptyParams ? {} : { ...node.#params }
 
           // Wildcard
           // '/hello/*/foo' => match /hello/bar/foo
           if (pattern === '*') {
             const astNode = node.#children['*']
             if (astNode) {
-              handlerSets.push(
-                ...this.#getHandlerSets(astNode, method, node.#params, Object.create(null))
-              )
+              handlerSets.push(...this.#getHandlerSets(astNode, method, node.#params))
               tempNodes.push(astNode)
             }
             continue
diff --git a/src/utils/mime.test.ts b/src/utils/mime.test.ts
index 70961c813..f89fbc06b 100644
--- a/src/utils/mime.test.ts
+++ b/src/utils/mime.test.ts
@@ -9,7 +9,7 @@ describe('mime', () => {
   it('getMimeType', () => {
     expect(getMimeType('hello.txt')).toBe('text/plain; charset=utf-8')
     expect(getMimeType('hello.html')).toBe('text/html; charset=utf-8')
-    expect(getMimeType('hello.json')).toBe('application/json; charset=utf-8')
+    expect(getMimeType('hello.json')).toBe('application/json')
     expect(getMimeType('favicon.ico')).toBe('image/x-icon')
     expect(getMimeType('good.morning.hello.gif')).toBe('image/gif')
     expect(getMimeType('goodmorninghellogif')).toBeUndefined()
diff --git a/src/utils/mime.ts b/src/utils/mime.ts
index 40f250af3..01aa08dc9 100644
--- a/src/utils/mime.ts
+++ b/src/utils/mime.ts
@@ -13,7 +13,7 @@ export const getMimeType = (
     return
   }
   let mimeType = mimes[match[1]]
-  if ((mimeType && mimeType.startsWith('text')) || mimeType === 'application/json') {
+  if (mimeType && mimeType.startsWith('text')) {
     mimeType += '; charset=utf-8'
   }
   return mimeType
diff --git a/src/validator/validator.test.ts b/src/validator/validator.test.ts
index 83af4481a..05ff812fd 100644
--- a/src/validator/validator.test.ts
+++ b/src/validator/validator.test.ts
@@ -140,7 +140,7 @@ describe('JSON', () => {
     const res = await app.request('http://localhost/post', {
       method: 'POST',
       headers: {
-        'Content-Type': 'application/json; charset=utf8',
+        'Content-Type': 'application/json',
       },
       body: JSON.stringify({ foo: 'bar' }),
     })