diff --git a/caps/tests/unit/test_uri_escaping.js b/caps/tests/unit/test_uri_escaping.js
index 5b388765fb13e..7feb58129557e 100644
--- a/caps/tests/unit/test_uri_escaping.js
+++ b/caps/tests/unit/test_uri_escaping.js
@@ -23,6 +23,6 @@ function run_test() {
 
   Assert.equal(
     createPrincipal("http://test/foo^bar").exposableSpec,
-    "http://test/foo^bar"
+    "http://test/foo%5Ebar"
   );
 }
diff --git a/netwerk/test/unit/test_standardurl.js b/netwerk/test/unit/test_standardurl.js
index 8917686130c72..b44289f2e6654 100644
--- a/netwerk/test/unit/test_standardurl.js
+++ b/netwerk/test/unit/test_standardurl.js
@@ -499,25 +499,6 @@ add_test(function test_hugeStringThrows() {
   run_next_test();
 });
 
-add_test(function test_caretNotEscaped() {
-  var url = stringToURL("wss://host/ !\"$%&'()*+,-./:;<=>@[\\]^_{|}~");
-  Assert.equal(
-    url.spec,
-    "wss://host/%20!%22$%&'()*+,-./:;%3C=%3E@[/]^_%7B|%7D~"
-  );
-
-  url = stringToURL("wss://host/abc^.bar");
-  Assert.equal(url.spec, "wss://host/abc^.bar");
-
-  url = stringToURL("wss://host/path/to/something?q=foo^bar");
-  Assert.equal(url.spec, "wss://host/path/to/something?q=foo^bar");
-
-  url = stringToURL("wss://host/#^");
-  Assert.equal(url.spec, "wss://host/#^");
-
-  run_next_test();
-});
-
 add_test(function test_filterWhitespace() {
   let url = stringToURL(
     " \r\n\th\nt\rt\tp://ex\r\n\tample.com/path\r\n\t/\r\n\tto the/fil\r\n\te.e\r\n\txt?que\r\n\try#ha\r\n\tsh \r\n\t "
diff --git a/testing/web-platform/meta/url/a-element-xhtml.xhtml.ini b/testing/web-platform/meta/url/a-element-xhtml.xhtml.ini
index 85cccd7a88c86..fc4eb05c251e2 100644
--- a/testing/web-platform/meta/url/a-element-xhtml.xhtml.ini
+++ b/testing/web-platform/meta/url/a-element-xhtml.xhtml.ini
@@ -596,6 +596,9 @@
   [Parsing: <foo://host/ !"$%&'()*+,-./:;<=>@[\\\]^_`{|}~> against <about:blank>]
     expected: FAIL
 
+  [Parsing: <wss://host/ !"$%&'()*+,-./:;<=>@[\\\]^_`{|}~> against <about:blank>]
+    expected: FAIL
+
   [Parsing: <foo://host/dir/? !"$%&'()*+,-./:;<=>?@[\\\]^_`{|}~> against <about:blank>]
     expected: FAIL
 
@@ -974,4 +977,8 @@
   [Parsing: <wss://!"$&'()*+,-.;=_`{}~/> against <about:blank>]
     expected: FAIL
 
+  [Parsing: <wss://host/ !"$%&'()*+,-./:;<=>@[\\\]^_`{|}~> against <about:blank>]
+    expected: FAIL
+
+
 [a-element-xhtml.xhtml?include=mailto]
diff --git a/testing/web-platform/meta/url/a-element.html.ini b/testing/web-platform/meta/url/a-element.html.ini
index 33a735bb2be97..6d698e54809ae 100644
--- a/testing/web-platform/meta/url/a-element.html.ini
+++ b/testing/web-platform/meta/url/a-element.html.ini
@@ -625,6 +625,9 @@
   [Parsing: <foo://host/ !"$%&'()*+,-./:;<=>@[\\\]^_`{|}~> against <about:blank>]
     expected: FAIL
 
+  [Parsing: <wss://host/ !"$%&'()*+,-./:;<=>@[\\\]^_`{|}~> against <about:blank>]
+    expected: FAIL
+
   [Parsing: <foo://host/dir/? !"$%&'()*+,-./:;<=>?@[\\\]^_`{|}~> against <about:blank>]
     expected: FAIL
 
@@ -1003,4 +1006,8 @@
   [Parsing: <wss://!"$&'()*+,-.;=_`{}~/> against <about:blank>]
     expected: FAIL
 
+  [Parsing: <wss://host/ !"$%&'()*+,-./:;<=>@[\\\]^_`{|}~> against <about:blank>]
+    expected: FAIL
+
+
 [a-element.html?include=mailto]
diff --git a/testing/web-platform/meta/url/url-constructor.any.js.ini b/testing/web-platform/meta/url/url-constructor.any.js.ini
index 8a4edb79f74f9..25bdaf4be70d5 100644
--- a/testing/web-platform/meta/url/url-constructor.any.js.ini
+++ b/testing/web-platform/meta/url/url-constructor.any.js.ini
@@ -403,6 +403,9 @@
   [Parsing: <foo://host/ !"$%&'()*+,-./:;<=>@[\\\]^_`{|}~> against <about:blank>]
     expected: FAIL
 
+  [Parsing: <wss://host/ !"$%&'()*+,-./:;<=>@[\\\]^_`{|}~> against <about:blank>]
+    expected: FAIL
+
   [Parsing: <foo://host/dir/? !"$%&'()*+,-./:;<=>?@[\\\]^_`{|}~> against <about:blank>]
     expected: FAIL
 
@@ -992,6 +995,9 @@
   [Parsing: <foo://host/ !"$%&'()*+,-./:;<=>@[\\\]^_`{|}~> against <about:blank>]
     expected: FAIL
 
+  [Parsing: <wss://host/ !"$%&'()*+,-./:;<=>@[\\\]^_`{|}~> against <about:blank>]
+    expected: FAIL
+
   [Parsing: <foo://host/dir/? !"$%&'()*+,-./:;<=>?@[\\\]^_`{|}~> against <about:blank>]
     expected: FAIL
 
@@ -1200,6 +1206,9 @@
   [Parsing: <wss://!"$&'()*+,-.;=_`{}~/> without base]
     expected: FAIL
 
+  [Parsing: <wss://host/ !"$%&'()*+,-./:;<=>@[\\\]^_`{|}~> without base]
+    expected: FAIL
+
 
 [url-constructor.any.html?include=file]
   [Parsing: <file:c:\\foo\\bar.html> against <file:///tmp/mock/path>]
@@ -1527,6 +1536,10 @@
   [Parsing: <wss://!"$&'()*+,-.;=_`{}~/> without base]
     expected: FAIL
 
+  [Parsing: <wss://host/ !"$%&'()*+,-./:;<=>@[\\\]^_`{|}~> without base]
+    expected: FAIL
+
+
 [url-constructor.any.html?include=javascript]
   [Parsing: <javascript:/../> without base]
     expected: FAIL
diff --git a/xpcom/io/nsEscape.cpp b/xpcom/io/nsEscape.cpp
index 353958dc77073..f211ea28096b3 100644
--- a/xpcom/io/nsEscape.cpp
+++ b/xpcom/io/nsEscape.cpp
@@ -278,9 +278,9 @@ static constexpr std::array<uint32_t, 256> BuildEscapeChars() {
   AddUnescapedChars("'.", esc_Username, table);
   AddUnescapedChars("'.", esc_Password, table);
   AddUnescapedChars(".", esc_Host, table);  // Same as esc_Scheme
-  AddUnescapedChars("'./:;=@[]^|", esc_Directory, table);
-  AddUnescapedChars("'.:;=@[]^|", esc_FileBaseName, table);
-  AddUnescapedChars("':;=@[]^|", esc_FileExtension, table);
+  AddUnescapedChars("'./:;=@[]|", esc_Directory, table);
+  AddUnescapedChars("'.:;=@[]|", esc_FileBaseName, table);
+  AddUnescapedChars("':;=@[]|", esc_FileExtension, table);
   AddUnescapedChars(".:;=@[\\]^`{|}", esc_Param, table);
   AddUnescapedChars("./:;=?@[\\]^`{|}", esc_Query, table);
   AddUnescapedChars("#'./:;=?@[\\]^{|}", esc_Ref, table);