diff --git a/src/compiler/compile/nodes/Element.ts b/src/compiler/compile/nodes/Element.ts
index 046d6252f3..a3e7cea192 100644
--- a/src/compiler/compile/nodes/Element.ts
+++ b/src/compiler/compile/nodes/Element.ts
@@ -399,7 +399,7 @@ export default class Element extends Node {
 			if (target_attribute && target_attribute.get_static_value() === '_blank' && href_attribute) {
 				const href_static_value = href_attribute.get_static_value() ? href_attribute.get_static_value().toLowerCase() : null;
 
-				if (href_static_value === null || href_static_value.startsWith('http') || href_static_value.startsWith('//')) {
+				if (href_static_value === null || href_static_value.match(/^(https?:)?\/\//i)) {
 					const rel = attribute_map.get('rel');
 					const rel_values = rel ? rel.get_static_value().split(' ') : [];
 					const expected_values = ['noopener', 'noreferrer'];
diff --git a/test/validator/samples/security-anchor-rel-noopener/input.svelte b/test/validator/samples/security-anchor-rel-noopener/input.svelte
index be146f6676..ec4aaaf7b3 100644
--- a/test/validator/samples/security-anchor-rel-noopener/input.svelte
+++ b/test/validator/samples/security-anchor-rel-noopener/input.svelte
@@ -19,6 +19,16 @@
 <a href="http://svelte.dev" target="_blank" rel="">svelte website (invalid)</a>
 <a href="http://svelte.dev" target="_blank" rel="noreferrer">svelte website (invalid)</a>
 <!-- svelte-ignore security-anchor-rel-noreferrer -->
+<a href="HTTP://svelte.dev" target="_blank" rel="">svelte website (invalid)</a>
+<a href="HTTP://svelte.dev" target="_blank" rel="noreferrer">svelte website (invalid)</a>
+<!-- svelte-ignore security-anchor-rel-noreferrer -->
+<a href="HTTPS://svelte.dev" target="_blank" rel="">svelte website (invalid)</a>
+<a href="HTTPS://svelte.dev" target="_blank" rel="noreferrer">svelte website (invalid)</a>
+<!-- svelte-ignore security-anchor-rel-noreferrer -->
+<a href="HTTP://svelte.dev" target="_blank">svelte website (invalid)</a>
+<!-- svelte-ignore security-anchor-rel-noreferrer -->
+<a href="HTTPS://svelte.dev" target="_blank">svelte website (invalid)</a>
+<!-- svelte-ignore security-anchor-rel-noreferrer -->
 <a href="same-host" target="_blank">Same host (valid)</a>
 <!-- svelte-ignore security-anchor-rel-noreferrer -->
 <a href="same-host" target="_blank" rel="">Same host (valid)</a>
@@ -30,5 +40,11 @@
 <a href="https://svelte.dev" target="_blank" rel="noopener">svelte website (valid)</a>
 <a href="https://svelte.dev" target="_blank" rel="noreferrer noopener">svelte website (valid)</a>
 <!-- svelte-ignore security-anchor-rel-noreferrer -->
+<a href="HTTP://svelte.dev" target="_blank" rel="noopener">svelte website (valid)</a>
+<a href="HTTP://svelte.dev" target="_blank" rel="noreferrer noopener">svelte website (valid)</a>
+<!-- svelte-ignore security-anchor-rel-noreferrer -->
+<a href="HTTPS://svelte.dev" target="_blank" rel="noopener">svelte website (valid)</a>
+<a href="HTTPS://svelte.dev" target="_blank" rel="noreferrer noopener">svelte website (valid)</a>
+<!-- svelte-ignore security-anchor-rel-noreferrer -->
 <a href="//svelte.dev" target="_blank" rel="noopener">svelte website (valid)</a>
 <a href="//svelte.dev" target="_blank" rel="noreferrer noopener">svelte website (valid)</a>
\ No newline at end of file
diff --git a/test/validator/samples/security-anchor-rel-noopener/warnings.json b/test/validator/samples/security-anchor-rel-noopener/warnings.json
index 6d4c77e7d3..352efb9050 100644
--- a/test/validator/samples/security-anchor-rel-noopener/warnings.json
+++ b/test/validator/samples/security-anchor-rel-noopener/warnings.json
@@ -178,5 +178,95 @@
 			"column": 0,
 			"line": 20
 		}
-	}
+	},
+	{
+		"code": "security-anchor-rel-noopener",
+		"end": {
+			"character": 1534,
+			"column": 79,
+			"line": 22
+		},
+		"message": "Security: Anchor with \"target=_blank\" should have rel attribute containing the value \"noopener\"",
+		"pos": 1455,
+		"start": {
+			"character": 1455,
+			"column": 0,
+			"line": 22
+		}
+	},
+	{
+		"code": "security-anchor-rel-noopener",
+		"end": {
+			"character": 1624,
+			"column": 89,
+			"line": 23
+		},
+		"message": "Security: Anchor with \"target=_blank\" should have rel attribute containing the value \"noopener\"",
+		"pos": 1535,
+		"start": {
+			"character": 1535,
+			"column": 0,
+			"line": 23
+		}
+	},
+	{
+		"code": "security-anchor-rel-noopener",
+		"end": {
+			"character": 1759,
+			"column": 80,
+			"line": 25
+		},
+		"message": "Security: Anchor with \"target=_blank\" should have rel attribute containing the value \"noopener\"",
+		"pos": 1679,
+		"start": {
+			"character": 1679,
+			"column": 0,
+			"line": 25
+		}
+	},
+	{
+		"code": "security-anchor-rel-noopener",
+		"end": {
+			"character": 1850,
+			"column": 90,
+			"line": 26
+		},
+		"message": "Security: Anchor with \"target=_blank\" should have rel attribute containing the value \"noopener\"",
+		"pos": 1760,
+		"start": {
+			"character": 1760,
+			"column": 0,
+			"line": 26
+		}
+	},
+	{
+		"code": "security-anchor-rel-noopener",
+		"end": {
+			"character": 1977,
+			"column": 72,
+			"line": 28
+		},
+		"message": "Security: Anchor with \"target=_blank\" should have rel attribute containing the value \"noopener\"",
+		"pos": 1905,
+		"start": {
+			"character": 1905,
+			"column": 0,
+			"line": 28
+		}
+	},
+	{
+		  "code": "security-anchor-rel-noopener",
+		  "end": {
+		    "character": 2105,
+		    "column": 73,
+		    "line": 30
+		  },
+		  "message": "Security: Anchor with \"target=_blank\" should have rel attribute containing the value \"noopener\"",
+		  "pos": 2032,
+		  "start": {
+		    "character": 2032,
+		    "column": 0,
+		    "line": 30
+		  }
+		}
 ]
\ No newline at end of file
diff --git a/test/validator/samples/security-anchor-rel-noreferrer/input.svelte b/test/validator/samples/security-anchor-rel-noreferrer/input.svelte
index 82248d28ef..62d62165fc 100644
--- a/test/validator/samples/security-anchor-rel-noreferrer/input.svelte
+++ b/test/validator/samples/security-anchor-rel-noreferrer/input.svelte
@@ -19,6 +19,16 @@
 <a href="http://svelte.dev" target="_blank" rel="">svelte website (invalid)</a>
 <a href="http://svelte.dev" target="_blank" rel="noopener">svelte website (invalid)</a>
 <!-- svelte-ignore security-anchor-rel-noopener -->
+<a href="HTTP://svelte.dev" target="_blank">svelte website (invalid)</a>
+<!-- svelte-ignore security-anchor-rel-noopener -->
+<a href="HTTP://svelte.dev" target="_blank" rel="">svelte website (invalid)</a>
+<a href="HTTP://svelte.dev" target="_blank" rel="noopener">svelte website (invalid)</a>
+<!-- svelte-ignore security-anchor-rel-noopener -->
+<a href={'HTTPS://svelte.dev'} target="_blank">svelte website (invalid)</a>
+<!-- svelte-ignore security-anchor-rel-noopener -->
+<a href={'HTTPS://svelte.dev'} target="_blank" rel="">svelte website (invalid)</a>
+<a href={'HTTPS://svelte.dev'} target="_blank" rel="noopener">svelte website (invalid)</a>
+<!-- svelte-ignore security-anchor-rel-noopener -->
 <a href="same-host" target="_blank">Same host (valid)</a>
 <!-- svelte-ignore security-anchor-rel-noopener -->
 <a href="same-host" target="_blank" rel="">Same host (valid)</a>
@@ -27,8 +37,14 @@
 <a href="http://svelte.dev" target="_blank" rel="noreferrer">svelte website (valid)</a>
 <a href="http://svelte.dev" target="_blank" rel="noreferrer noopener">svelte website (valid)</a>
 <!-- svelte-ignore security-anchor-rel-noopener -->
+<a href="HTTP://svelte.dev" target="_blank" rel="noreferrer">svelte website (valid)</a>
+<a href="HTTP://svelte.dev" target="_blank" rel="noreferrer noopener">svelte website (valid)</a>
+<!-- svelte-ignore security-anchor-rel-noopener -->
 <a href="https://svelte.dev" target="_blank" rel="noreferrer">svelte website (valid)</a>
 <a href="https://svelte.dev" target="_blank" rel="noreferrer noopener">svelte website (valid)</a>
 <!-- svelte-ignore security-anchor-rel-noopener -->
+<a href="HTTPS://svelte.dev" target="_blank" rel="noreferrer">svelte website (valid)</a>
+<a href="HTTPS://svelte.dev" target="_blank" rel="noreferrer noopener">svelte website (valid)</a>
+<!-- svelte-ignore security-anchor-rel-noopener -->
 <a href="//svelte.dev" target="_blank" rel="noreferrer">svelte website (valid)</a>
 <a href="//svelte.dev" target="_blank" rel="noreferrer noopener">svelte website (valid)</a>
\ No newline at end of file
diff --git a/test/validator/samples/security-anchor-rel-noreferrer/warnings.json b/test/validator/samples/security-anchor-rel-noreferrer/warnings.json
index 5581b3e449..1608c87e5b 100644
--- a/test/validator/samples/security-anchor-rel-noreferrer/warnings.json
+++ b/test/validator/samples/security-anchor-rel-noreferrer/warnings.json
@@ -178,5 +178,95 @@
 			"column": 0,
 			"line": 20
 		}
-	}
+	},
+	{
+		  "code": "security-anchor-rel-noreferrer",
+		  "end": {
+		    "character": 1501,
+		    "column": 72,
+		    "line": 22
+		  },
+		  "message": "Security: Anchor with \"target=_blank\" should have rel attribute containing the value \"noreferrer\"",
+		  "pos": 1429,
+		  "start": {
+		    "character": 1429,
+		    "column": 0,
+		    "line": 22
+		  }
+		},
+		{
+		  "code": "security-anchor-rel-noreferrer",
+		  "end": {
+		    "character": 1633,
+		    "column": 79,
+		    "line": 24
+		  },
+		  "message": "Security: Anchor with \"target=_blank\" should have rel attribute containing the value \"noreferrer\"",
+		  "pos": 1554,
+		  "start": {
+		    "character": 1554,
+		    "column": 0,
+		    "line": 24
+		  }
+		},
+		{
+		  "code": "security-anchor-rel-noreferrer",
+		  "end": {
+		    "character": 1721,
+		    "column": 87,
+		    "line": 25
+		  },
+		  "message": "Security: Anchor with \"target=_blank\" should have rel attribute containing the value \"noreferrer\"",
+		  "pos": 1634,
+		  "start": {
+		    "character": 1634,
+		    "column": 0,
+		    "line": 25
+		  }
+		},
+		{
+		  "code": "security-anchor-rel-noreferrer",
+		  "end": {
+		    "character": 1849,
+		    "column": 75,
+		    "line": 27
+		  },
+		  "message": "Security: Anchor with \"target=_blank\" should have rel attribute containing the value \"noreferrer\"",
+		  "pos": 1774,
+		  "start": {
+		    "character": 1774,
+		    "column": 0,
+		    "line": 27
+		  }
+		},
+		{
+		  "code": "security-anchor-rel-noreferrer",
+		  "end": {
+		    "character": 1984,
+		    "column": 82,
+		    "line": 29
+		  },
+		  "message": "Security: Anchor with \"target=_blank\" should have rel attribute containing the value \"noreferrer\"",
+		  "pos": 1902,
+		  "start": {
+		    "character": 1902,
+		    "column": 0,
+		    "line": 29
+		  }
+		},
+		{
+		  "code": "security-anchor-rel-noreferrer",
+		  "end": {
+		    "character": 2075,
+		    "column": 90,
+		    "line": 30
+		  },
+		  "message": "Security: Anchor with \"target=_blank\" should have rel attribute containing the value \"noreferrer\"",
+		  "pos": 1985,
+		  "start": {
+		    "character": 1985,
+		    "column": 0,
+		    "line": 30
+		  }
+		}
 ]
\ No newline at end of file