diff --git a/src/html/template/escape_test.go b/src/html/template/escape_test.go
index aef5e01957..5ff1734202 100644
--- a/src/html/template/escape_test.go
+++ b/src/html/template/escape_test.go
@@ -760,6 +760,26 @@ func TestEscape(t *testing.T) {
 			`<meta http-equiv="refresh" content="{{"asd: 123"}}">`,
 			`<meta http-equiv="refresh" content="asd: 123">`,
 		},
+		{
+			"meta content url with whitespace before equals",
+			`<meta http-equiv="refresh" content="0;url ={{"javascript:alert(1)"}}">`,
+			`<meta http-equiv="refresh" content="0;url =#ZgotmplZ">`,
+		},
+		{
+			"meta content url with tab before equals",
+			"<meta http-equiv=\"refresh\" content=\"0;url\t={{\"javascript:alert(1)\"}}\">",
+			"<meta http-equiv=\"refresh\" content=\"0;url\t=#ZgotmplZ\">",
+		},
+		{
+			"meta content url with space after equals",
+			`<meta http-equiv="refresh" content="0;url= {{"javascript:alert(1)"}}">`,
+			`<meta http-equiv="refresh" content="0;url= #ZgotmplZ">`,
+		},
+		{
+			"meta content url with whitespace both sides of equals",
+			"<meta http-equiv=\"refresh\" content=\"0;url \t= {{\"javascript:alert(1)\"}}\">",
+			"<meta http-equiv=\"refresh\" content=\"0;url \t= #ZgotmplZ\">",
+		},
 	}
 
 	for _, test := range tests {
diff --git a/src/html/template/transition.go b/src/html/template/transition.go
index 7fbab1df7b..ea4b272cc2 100644
--- a/src/html/template/transition.go
+++ b/src/html/template/transition.go
@@ -626,10 +626,12 @@ func tError(c context, s []byte) (context, int) {
 
 // tMetaContent is the context transition function for the meta content attribute state.
 func tMetaContent(c context, s []byte) (context, int) {
-	for i := 0; i < len(s); i++ {
-		if i+3 <= len(s)-1 && bytes.Equal(bytes.ToLower(s[i:i+4]), []byte("url=")) {
-			c.state = stateMetaContentURL
-			return c, i + 4
+	for i := range len(s) {
+		if i+3 <= len(s)-1 && bytes.EqualFold(s[i:i+3], []byte("url")) {
+			if j := eatWhiteSpace(s, i+3); j < len(s) && s[j] == '=' {
+				c.state = stateMetaContentURL
+				return c, j + 1
+			}
 		}
 	}
 	return c, len(s)
@@ -637,7 +639,7 @@ func tMetaContent(c context, s []byte) (context, int) {
 
 // tMetaContentURL is the context transition function for the "url=" part of a meta content attribute state.
 func tMetaContentURL(c context, s []byte) (context, int) {
-	for i := 0; i < len(s); i++ {
+	for i := range len(s) {
 		if s[i] == ';' {
 			c.state = stateMetaContent
 			return c, i + 1