diff --git a/dev-packages/e2e-tests/test-applications/nextjs-16/tests/middleware.test.ts b/dev-packages/e2e-tests/test-applications/nextjs-16/tests/middleware.test.ts
index 0bb957bbc466..5386c75f31a9 100644
--- a/dev-packages/e2e-tests/test-applications/nextjs-16/tests/middleware.test.ts
+++ b/dev-packages/e2e-tests/test-applications/nextjs-16/tests/middleware.test.ts
@@ -7,6 +7,10 @@ test('Should create a transaction for middleware', async ({ request }) => {
     return transactionEvent?.transaction === 'middleware GET';
   });
 
+  const routeTransactionPromise = waitForTransaction('nextjs-16', async transactionEvent => {
+    return transactionEvent?.transaction === 'GET /api/endpoint-behind-middleware';
+  });
+
   const response = await request.get('/api/endpoint-behind-middleware');
   expect(await response.json()).toStrictEqual({ name: 'John Doe' });
 
@@ -20,6 +24,12 @@ test('Should create a transaction for middleware', async ({ request }) => {
   // Assert that isolation scope works properly
   expect(middlewareTransaction.tags?.['my-isolated-tag']).toBe(true);
   expect(middlewareTransaction.tags?.['my-global-scope-isolated-tag']).not.toBeDefined();
+
+  // Tags set in middleware must not leak into other requests' events (e.g. via a shared scope when the middleware
+  // runs in a detached context - https://github.com/vercel/next.js/pull/95306)
+  const routeTransaction = await routeTransactionPromise;
+  expect(routeTransaction.tags?.['my-isolated-tag']).not.toBeDefined();
+  expect(routeTransaction.tags?.['my-global-scope-isolated-tag']).not.toBeDefined();
 });
 
 test('Faulty middlewares', async ({ request }) => {
diff --git a/packages/nextjs/src/edge/enhanceMiddlewareRootSpan.ts b/packages/nextjs/src/common/enhanceMiddlewareRootSpan.ts
similarity index 61%
rename from packages/nextjs/src/edge/enhanceMiddlewareRootSpan.ts
rename to packages/nextjs/src/common/enhanceMiddlewareRootSpan.ts
index cd71928e9109..27a4cc5e5425 100644
--- a/packages/nextjs/src/edge/enhanceMiddlewareRootSpan.ts
+++ b/packages/nextjs/src/common/enhanceMiddlewareRootSpan.ts
@@ -1,24 +1,23 @@
 import { stripUrlQueryAndFragment } from '@sentry/core';
-import { ATTR_NEXT_SPAN_NAME, ATTR_NEXT_SPAN_TYPE } from '../common/nextSpanAttributes';
+import { ATTR_NEXT_SPAN_NAME, ATTR_NEXT_SPAN_TYPE } from './nextSpanAttributes';
 
 export interface MutableMiddlewareRootSpan {
   attributes: Record<string, unknown>;
   getName(): string | undefined;
   setName(name: string): void;
+  setOp(op: string): void;
 }
 
 /**
- * Normalizes the transaction name for the root span of a Next.js `Middleware.execute` request on the Edge runtime.
+ * Normalizes the transaction name and op for the root span of a Next.js `Middleware.execute` request.
+ *
+ * On the Edge runtime, middleware always runs in a detached sandbox, so `Middleware.execute` is the root span.
+ * On the Node.js runtime, this is the case since vercel/next.js#95306, where in-process
+ * middleware runs in a detached OTel context instead of inside the `BaseServer.handleRequest` span.
  *
  * Older Next.js versions append the full URL to the middleware span name (e.g. `middleware GET /foo?bar=1`),
  * producing high-cardinality transaction names. We collapse the name to `middleware {METHOD}` when possible,
  * and strip query/fragment otherwise.
- *
- * Called from two places that operate on different shapes of the same underlying root span:
- * - Legacy mode: from `preprocessEvent`, adapted around a transaction `Event` whose `contexts.trace.data`
- *   holds the root span's attributes and whose `event.transaction` is the root span's name.
- * - Streamed mode: from `processSegmentSpan`, adapted around a `StreamedSpanJSON` (the streamed
- *   counterpart of the legacy transaction root) directly.
  */
 export function enhanceMiddlewareRootSpan(span: MutableMiddlewareRootSpan): void {
   const { attributes } = span;
@@ -27,6 +26,8 @@ export function enhanceMiddlewareRootSpan(span: MutableMiddlewareRootSpan): void
     return;
   }
 
+  span.setOp('http.server.middleware');
+
   const spanName = attributes[ATTR_NEXT_SPAN_NAME];
   if (typeof spanName !== 'string' || !spanName || !span.getName()) {
     return;
diff --git a/packages/nextjs/src/edge/index.ts b/packages/nextjs/src/edge/index.ts
index 7bb24bbf6c8d..4025f43dc777 100644
--- a/packages/nextjs/src/edge/index.ts
+++ b/packages/nextjs/src/edge/index.ts
@@ -29,7 +29,7 @@ import { isBuild } from '../common/utils/isBuild';
 import { flushSafelyWithTimeout, isCloudflareWaitUntilAvailable, waitUntil } from '../common/utils/responseEnd';
 import { setUrlProcessingMetadata } from '../common/utils/setUrlProcessingMetadata';
 import { distDirRewriteFramesIntegration } from './distDirRewriteFramesIntegration';
-import { enhanceMiddlewareRootSpan } from './enhanceMiddlewareRootSpan';
+import { enhanceMiddlewareRootSpan } from '../common/enhanceMiddlewareRootSpan';
 
 export * from '@sentry/vercel-edge';
 export * from '../common';
@@ -155,6 +155,9 @@ export function init(options: VercelEdgeOptions = {}): void {
         setName: name => {
           event.transaction = name;
         },
+        setOp: op => {
+          event.contexts!.trace!.op = op;
+        },
       });
     }
 
@@ -171,6 +174,9 @@ export function init(options: VercelEdgeOptions = {}): void {
       setName: name => {
         span.name = name;
       },
+      setOp: op => {
+        attributes[SEMANTIC_ATTRIBUTE_SENTRY_OP] = op;
+      },
     });
   });
 
diff --git a/packages/nextjs/src/server/handleOnSpanStart.ts b/packages/nextjs/src/server/handleOnSpanStart.ts
index 101e61f05232..a59124a3a244 100644
--- a/packages/nextjs/src/server/handleOnSpanStart.ts
+++ b/packages/nextjs/src/server/handleOnSpanStart.ts
@@ -84,8 +84,13 @@ export function handleOnSpanStart(span: Span): void {
     addHeadersAsAttributes(headers, rootSpan);
   }
 
-  // We want to fork the isolation scope for incoming requests
-  if (spanAttributes?.[ATTR_NEXT_SPAN_TYPE] === 'BaseServer.handleRequest' && isRootSpan) {
+  // We want to fork the isolation scope for incoming requests. Root `Middleware.execute` spans need the same
+  // treatment since Next.js 16.3.0-canary.79
+  if (
+    (spanAttributes?.[ATTR_NEXT_SPAN_TYPE] === 'BaseServer.handleRequest' ||
+      spanAttributes?.[ATTR_NEXT_SPAN_TYPE] === 'Middleware.execute') &&
+    isRootSpan
+  ) {
     const scopes = getCapturedScopesOnSpan(span);
 
     const isolationScope = (scopes.isolationScope || getIsolationScope()).clone();
diff --git a/packages/nextjs/src/server/index.ts b/packages/nextjs/src/server/index.ts
index cd70361506c8..246c00c28fd8 100644
--- a/packages/nextjs/src/server/index.ts
+++ b/packages/nextjs/src/server/index.ts
@@ -21,6 +21,7 @@ import { isBuild } from '../common/utils/isBuild';
 import { isCloudflareWaitUntilAvailable } from '../common/utils/responseEnd';
 import { setUrlProcessingMetadata } from '../common/utils/setUrlProcessingMetadata';
 import { distDirRewriteFramesIntegration } from './distDirRewriteFramesIntegration';
+import { enhanceMiddlewareRootSpan } from '../common/enhanceMiddlewareRootSpan';
 import { enhanceHandleRequestRootSpan } from './enhanceHandleRequestRootSpan';
 import { handleOnSpanStart } from './handleOnSpanStart';
 import { prepareSafeIdGeneratorContext } from './prepareSafeIdGeneratorContext';
@@ -249,16 +250,18 @@ export function init(options: NodeOptions): NodeClient | undefined {
   // Span streaming bypasses event processors entirely - see the `processSegmentSpan` hook below for that path.
   client?.on('preprocessEvent', event => {
     if (event.type === 'transaction' && event.contexts?.trace?.data) {
-      enhanceHandleRequestRootSpan({
+      const mutableRootSpan = {
         attributes: event.contexts.trace.data,
         getName: () => event.transaction,
-        setName: name => {
+        setName: (name: string) => {
           event.transaction = name;
         },
-        setOp: op => {
+        setOp: (op: string) => {
           event.contexts!.trace!.op = op;
         },
-      });
+      };
+      enhanceHandleRequestRootSpan(mutableRootSpan);
+      enhanceMiddlewareRootSpan(mutableRootSpan);
     }
 
     setUrlProcessingMetadata(event);
@@ -268,18 +271,20 @@ export function init(options: NodeOptions): NodeClient | undefined {
   // transaction events, so the same enhancement has to be applied here directly on the span JSON.
   client?.on('processSegmentSpan', span => {
     const attributes = (span.attributes ??= {});
-    enhanceHandleRequestRootSpan({
+    const mutableRootSpan = {
       attributes,
       getName: () => span.name,
-      setName: name => {
+      setName: (name: string) => {
         span.name = name;
       },
       // For streamed spans, op lives in `attributes['sentry.op']` - mirror it there so middleware
       // overrides land somewhere readable (the legacy path uses a separate `event.contexts.trace.op`).
-      setOp: op => {
+      setOp: (op: string) => {
         attributes[SEMANTIC_ATTRIBUTE_SENTRY_OP] = op;
       },
-    });
+    };
+    enhanceHandleRequestRootSpan(mutableRootSpan);
+    enhanceMiddlewareRootSpan(mutableRootSpan);
   });
 
   if (process.env.NODE_ENV === 'development') {
diff --git a/packages/nextjs/test/edge/enhanceMiddlewareRootSpan.test.ts b/packages/nextjs/test/common/enhanceMiddlewareRootSpan.test.ts
similarity index 61%
rename from packages/nextjs/test/edge/enhanceMiddlewareRootSpan.test.ts
rename to packages/nextjs/test/common/enhanceMiddlewareRootSpan.test.ts
index 6308c6a75bab..edd3ab52fef3 100644
--- a/packages/nextjs/test/edge/enhanceMiddlewareRootSpan.test.ts
+++ b/packages/nextjs/test/common/enhanceMiddlewareRootSpan.test.ts
@@ -1,9 +1,10 @@
 import { describe, expect, it } from 'vitest';
+import { enhanceMiddlewareRootSpan } from '../../src/common/enhanceMiddlewareRootSpan';
 import { ATTR_NEXT_SPAN_NAME, ATTR_NEXT_SPAN_TYPE } from '../../src/common/nextSpanAttributes';
-import { enhanceMiddlewareRootSpan } from '../../src/edge/enhanceMiddlewareRootSpan';
 
 function makeSpan(attributes: Record<string, unknown>, name?: string) {
   let currentName = name;
+  let currentOp: string | undefined;
   return {
     span: {
       attributes,
@@ -11,14 +12,18 @@ function makeSpan(attributes: Record<string, unknown>, name?: string) {
       setName: (n: string) => {
         currentName = n;
       },
+      setOp: (op: string) => {
+        currentOp = op;
+      },
     },
     getName: () => currentName,
+    getOp: () => currentOp,
   };
 }
 
 describe('enhanceMiddlewareRootSpan', () => {
   it('does nothing for spans that are not Middleware.execute', () => {
-    const { span, getName } = makeSpan(
+    const { span, getName, getOp } = makeSpan(
       { [ATTR_NEXT_SPAN_TYPE]: 'BaseServer.handleRequest', [ATTR_NEXT_SPAN_NAME]: 'middleware GET /foo' },
       'GET /foo',
     );
@@ -26,18 +31,20 @@ describe('enhanceMiddlewareRootSpan', () => {
     enhanceMiddlewareRootSpan(span);
 
     expect(getName()).toBe('GET /foo');
+    expect(getOp()).toBeUndefined();
   });
 
-  it('does nothing when next.span_name is missing', () => {
-    const { span, getName } = makeSpan({ [ATTR_NEXT_SPAN_TYPE]: 'Middleware.execute' }, 'middleware');
+  it('sets the op but keeps the name when next.span_name is missing', () => {
+    const { span, getName, getOp } = makeSpan({ [ATTR_NEXT_SPAN_TYPE]: 'Middleware.execute' }, 'middleware');
 
     enhanceMiddlewareRootSpan(span);
 
     expect(getName()).toBe('middleware');
+    expect(getOp()).toBe('http.server.middleware');
   });
 
-  it('does nothing when next.span_name is an empty string', () => {
-    const { span, getName } = makeSpan(
+  it('sets the op but keeps the name when next.span_name is an empty string', () => {
+    const { span, getName, getOp } = makeSpan(
       { [ATTR_NEXT_SPAN_TYPE]: 'Middleware.execute', [ATTR_NEXT_SPAN_NAME]: '' },
       'middleware',
     );
@@ -45,10 +52,11 @@ describe('enhanceMiddlewareRootSpan', () => {
     enhanceMiddlewareRootSpan(span);
 
     expect(getName()).toBe('middleware');
+    expect(getOp()).toBe('http.server.middleware');
   });
 
-  it('does nothing when next.span_name is not a string', () => {
-    const { span, getName } = makeSpan(
+  it('sets the op but keeps the name when next.span_name is not a string', () => {
+    const { span, getName, getOp } = makeSpan(
       { [ATTR_NEXT_SPAN_TYPE]: 'Middleware.execute', [ATTR_NEXT_SPAN_NAME]: 123 },
       'middleware',
     );
@@ -56,10 +64,11 @@ describe('enhanceMiddlewareRootSpan', () => {
     enhanceMiddlewareRootSpan(span);
 
     expect(getName()).toBe('middleware');
+    expect(getOp()).toBe('http.server.middleware');
   });
 
-  it('does nothing when the current name is empty', () => {
-    const { span, getName } = makeSpan(
+  it('sets the op but keeps the name when the current name is empty', () => {
+    const { span, getName, getOp } = makeSpan(
       { [ATTR_NEXT_SPAN_TYPE]: 'Middleware.execute', [ATTR_NEXT_SPAN_NAME]: 'middleware GET /foo' },
       undefined,
     );
@@ -67,6 +76,7 @@ describe('enhanceMiddlewareRootSpan', () => {
     enhanceMiddlewareRootSpan(span);
 
     expect(getName()).toBeUndefined();
+    expect(getOp()).toBe('http.server.middleware');
   });
 
   it.each([
@@ -75,7 +85,7 @@ describe('enhanceMiddlewareRootSpan', () => {
     ['middleware DELETE /resources/[id]', 'middleware DELETE'],
     ['middleware HEAD /', 'middleware HEAD'],
   ])('collapses "%s" to "%s"', (spanName, expected) => {
-    const { span, getName } = makeSpan(
+    const { span, getName, getOp } = makeSpan(
       { [ATTR_NEXT_SPAN_TYPE]: 'Middleware.execute', [ATTR_NEXT_SPAN_NAME]: spanName },
       spanName,
     );
@@ -83,6 +93,21 @@ describe('enhanceMiddlewareRootSpan', () => {
     enhanceMiddlewareRootSpan(span);
 
     expect(getName()).toBe(expected);
+    expect(getOp()).toBe('http.server.middleware');
+  });
+
+  it('normalizes the plain "middleware {METHOD}" name emitted for Node.js middleware', () => {
+    // Node.js middleware roots come pre-mangled by HTTP span inference (e.g. `GET middleware GET`),
+    // while `next.span_name` holds the original `middleware GET`.
+    const { span, getName, getOp } = makeSpan(
+      { [ATTR_NEXT_SPAN_TYPE]: 'Middleware.execute', [ATTR_NEXT_SPAN_NAME]: 'middleware GET' },
+      'GET middleware GET',
+    );
+
+    enhanceMiddlewareRootSpan(span);
+
+    expect(getName()).toBe('middleware GET');
+    expect(getOp()).toBe('http.server.middleware');
   });
 
   it('strips query and fragment from non-method-prefixed middleware names', () => {