diff --git a/packages/compiler-core/__tests__/__snapshots__/parse.spec.ts.snap b/packages/compiler-core/__tests__/__snapshots__/parse.spec.ts.snap
index 942eed4c4dc..95fa532a4f1 100644
--- a/packages/compiler-core/__tests__/__snapshots__/parse.spec.ts.snap
+++ b/packages/compiler-core/__tests__/__snapshots__/parse.spec.ts.snap
@@ -2444,6 +2444,113 @@ exports[`compiler: parse > Errors > MISSING_END_TAG_NAME > <template></></templa
 }
 `;
 
+exports[`compiler: parse > Errors > UNEXPECTED_CHARACTER_IN_ATTRIBUTE_NAME > <template><div "></div></template> 1`] = `
+{
+  "cached": [],
+  "children": [
+    {
+      "children": [
+        {
+          "children": [],
+          "codegenNode": undefined,
+          "loc": {
+            "end": {
+              "column": 24,
+              "line": 1,
+              "offset": 23,
+            },
+            "source": "<div "></div>",
+            "start": {
+              "column": 11,
+              "line": 1,
+              "offset": 10,
+            },
+          },
+          "ns": 0,
+          "props": [
+            {
+              "loc": {
+                "end": {
+                  "column": 17,
+                  "line": 1,
+                  "offset": 16,
+                },
+                "source": """,
+                "start": {
+                  "column": 16,
+                  "line": 1,
+                  "offset": 15,
+                },
+              },
+              "name": """,
+              "nameLoc": {
+                "end": {
+                  "column": 17,
+                  "line": 1,
+                  "offset": 16,
+                },
+                "source": """,
+                "start": {
+                  "column": 16,
+                  "line": 1,
+                  "offset": 15,
+                },
+              },
+              "type": 6,
+              "value": undefined,
+            },
+          ],
+          "tag": "div",
+          "tagType": 0,
+          "type": 1,
+        },
+      ],
+      "codegenNode": undefined,
+      "loc": {
+        "end": {
+          "column": 35,
+          "line": 1,
+          "offset": 34,
+        },
+        "source": "<template><div "></div></template>",
+        "start": {
+          "column": 1,
+          "line": 1,
+          "offset": 0,
+        },
+      },
+      "ns": 0,
+      "props": [],
+      "tag": "template",
+      "tagType": 0,
+      "type": 1,
+    },
+  ],
+  "codegenNode": undefined,
+  "components": [],
+  "directives": [],
+  "helpers": Set {},
+  "hoists": [],
+  "imports": [],
+  "loc": {
+    "end": {
+      "column": 35,
+      "line": 1,
+      "offset": 34,
+    },
+    "source": "<template><div "></div></template>",
+    "start": {
+      "column": 1,
+      "line": 1,
+      "offset": 0,
+    },
+  },
+  "source": "<template><div "></div></template>",
+  "temps": 0,
+  "type": 0,
+}
+`;
+
 exports[`compiler: parse > Errors > UNEXPECTED_CHARACTER_IN_ATTRIBUTE_NAME > <template><div a"bc=''></div></template> 1`] = `
 {
   "cached": [],
@@ -2813,6 +2920,144 @@ exports[`compiler: parse > Errors > UNEXPECTED_CHARACTER_IN_ATTRIBUTE_NAME > <te
 }
 `;
 
+exports[`compiler: parse > Errors > UNEXPECTED_CHARACTER_IN_ATTRIBUTE_NAME > <template><div foo "></div></template> 1`] = `
+{
+  "cached": [],
+  "children": [
+    {
+      "children": [
+        {
+          "children": [],
+          "codegenNode": undefined,
+          "loc": {
+            "end": {
+              "column": 28,
+              "line": 1,
+              "offset": 27,
+            },
+            "source": "<div foo "></div>",
+            "start": {
+              "column": 11,
+              "line": 1,
+              "offset": 10,
+            },
+          },
+          "ns": 0,
+          "props": [
+            {
+              "loc": {
+                "end": {
+                  "column": 19,
+                  "line": 1,
+                  "offset": 18,
+                },
+                "source": "foo",
+                "start": {
+                  "column": 16,
+                  "line": 1,
+                  "offset": 15,
+                },
+              },
+              "name": "foo",
+              "nameLoc": {
+                "end": {
+                  "column": 19,
+                  "line": 1,
+                  "offset": 18,
+                },
+                "source": "foo",
+                "start": {
+                  "column": 16,
+                  "line": 1,
+                  "offset": 15,
+                },
+              },
+              "type": 6,
+              "value": undefined,
+            },
+            {
+              "loc": {
+                "end": {
+                  "column": 21,
+                  "line": 1,
+                  "offset": 20,
+                },
+                "source": """,
+                "start": {
+                  "column": 20,
+                  "line": 1,
+                  "offset": 19,
+                },
+              },
+              "name": """,
+              "nameLoc": {
+                "end": {
+                  "column": 21,
+                  "line": 1,
+                  "offset": 20,
+                },
+                "source": """,
+                "start": {
+                  "column": 20,
+                  "line": 1,
+                  "offset": 19,
+                },
+              },
+              "type": 6,
+              "value": undefined,
+            },
+          ],
+          "tag": "div",
+          "tagType": 0,
+          "type": 1,
+        },
+      ],
+      "codegenNode": undefined,
+      "loc": {
+        "end": {
+          "column": 39,
+          "line": 1,
+          "offset": 38,
+        },
+        "source": "<template><div foo "></div></template>",
+        "start": {
+          "column": 1,
+          "line": 1,
+          "offset": 0,
+        },
+      },
+      "ns": 0,
+      "props": [],
+      "tag": "template",
+      "tagType": 0,
+      "type": 1,
+    },
+  ],
+  "codegenNode": undefined,
+  "components": [],
+  "directives": [],
+  "helpers": Set {},
+  "hoists": [],
+  "imports": [],
+  "loc": {
+    "end": {
+      "column": 39,
+      "line": 1,
+      "offset": 38,
+    },
+    "source": "<template><div foo "></div></template>",
+    "start": {
+      "column": 1,
+      "line": 1,
+      "offset": 0,
+    },
+  },
+  "source": "<template><div foo "></div></template>",
+  "temps": 0,
+  "type": 0,
+}
+`;
+
 exports[`compiler: parse > Errors > UNEXPECTED_CHARACTER_IN_UNQUOTED_ATTRIBUTE_VALUE > <template><div foo=bar"></div></template> 1`] = `
 {
   "cached": [],
@@ -3451,39 +3696,7 @@ exports[`compiler: parse > Errors > UNEXPECTED_EQUALS_SIGN_BEFORE_ATTRIBUTE_NAME
             },
           },
           "ns": 0,
-          "props": [
-            {
-              "loc": {
-                "end": {
-                  "column": 17,
-                  "line": 1,
-                  "offset": 16,
-                },
-                "source": "=",
-                "start": {
-                  "column": 16,
-                  "line": 1,
-                  "offset": 15,
-                },
-              },
-              "name": "=",
-              "nameLoc": {
-                "end": {
-                  "column": 17,
-                  "line": 1,
-                  "offset": 16,
-                },
-                "source": "=",
-                "start": {
-                  "column": 16,
-                  "line": 1,
-                  "offset": 15,
-                },
-              },
-              "type": 6,
-              "value": undefined,
-            },
-          ],
+          "props": [],
           "tag": "div",
           "tagType": 0,
           "type": 1,
@@ -3566,25 +3779,25 @@ exports[`compiler: parse > Errors > UNEXPECTED_EQUALS_SIGN_BEFORE_ATTRIBUTE_NAME
                   "line": 1,
                   "offset": 23,
                 },
-                "source": "=foo=bar",
+                "source": "foo=bar",
                 "start": {
-                  "column": 16,
+                  "column": 17,
                   "line": 1,
-                  "offset": 15,
+                  "offset": 16,
                 },
               },
-              "name": "=foo",
+              "name": "foo",
               "nameLoc": {
                 "end": {
                   "column": 20,
                   "line": 1,
                   "offset": 19,
                 },
-                "source": "=foo",
+                "source": "foo",
                 "start": {
-                  "column": 16,
+                  "column": 17,
                   "line": 1,
-                  "offset": 15,
+                  "offset": 16,
                 },
               },
               "type": 6,
diff --git a/packages/compiler-core/__tests__/parse.spec.ts b/packages/compiler-core/__tests__/parse.spec.ts
index cdc2b09fd48..dd21bb30d45 100644
--- a/packages/compiler-core/__tests__/parse.spec.ts
+++ b/packages/compiler-core/__tests__/parse.spec.ts
@@ -3210,6 +3210,24 @@ describe('compiler: parse', () => {
             },
           ],
         },
+        {
+          code: '<template><div "></div></template>',
+          errors: [
+            {
+              type: ErrorCodes.UNEXPECTED_CHARACTER_IN_ATTRIBUTE_NAME,
+              loc: { offset: 15, line: 1, column: 16 },
+            },
+          ],
+        },
+        {
+          code: '<template><div foo "></div></template>',
+          errors: [
+            {
+              type: ErrorCodes.UNEXPECTED_CHARACTER_IN_ATTRIBUTE_NAME,
+              loc: { offset: 19, line: 1, column: 20 },
+            },
+          ],
+        },
       ],
       UNEXPECTED_CHARACTER_IN_UNQUOTED_ATTRIBUTE_VALUE: [
         {
diff --git a/packages/compiler-core/src/tokenizer.ts b/packages/compiler-core/src/tokenizer.ts
index b8a74790259..f4b4dcba5f1 100644
--- a/packages/compiler-core/src/tokenizer.ts
+++ b/packages/compiler-core/src/tokenizer.ts
@@ -651,17 +651,16 @@ export default class Tokenizer {
       this.state = State.BeforeTagName
       this.sectionStart = this.index
     } else if (!isWhitespace(c)) {
-      if ((__DEV__ || !__BROWSER__) && c === CharCodes.Eq) {
-        this.cbs.onerr(
-          ErrorCodes.UNEXPECTED_EQUALS_SIGN_BEFORE_ATTRIBUTE_NAME,
-          this.index,
-        )
-      }
       this.handleAttrStart(c)
     }
   }
   private handleAttrStart(c: number) {
-    if (c === CharCodes.LowerV && this.peek() === CharCodes.Dash) {
+    if ((__DEV__ || !__BROWSER__) && c === CharCodes.Eq) {
+      this.cbs.onerr(
+        ErrorCodes.UNEXPECTED_EQUALS_SIGN_BEFORE_ATTRIBUTE_NAME,
+        this.index,
+      )
+    } else if (c === CharCodes.LowerV && this.peek() === CharCodes.Dash) {
       this.state = State.InDirName
       this.sectionStart = this.index
     } else if (
@@ -676,6 +675,7 @@ export default class Tokenizer {
     } else {
       this.state = State.InAttrName
       this.sectionStart = this.index
+      this.stateInAttrName(c)
     }
   }
   private stateInSelfClosingTag(c: number): void {