diff --git a/src/net/mail/message.go b/src/net/mail/message.go
index 75207db..0781310 100644
--- a/src/net/mail/message.go
+++ b/src/net/mail/message.go
@@ -79,7 +79,7 @@
 	years := [...]string{"2006", "06"} // year = 4*DIGIT / 2*DIGIT
 	seconds := [...]string{":05", ""}  // second
 	// "-0700 (MST)" is not in RFC 5322, but is common.
-	zones := [...]string{"-0700", "MST", "-0700 (MST)"} // zone = (("+" / "-") 4DIGIT) / "GMT" / ...
+	zones := [...]string{"-0700", "MST"} // zone = (("+" / "-") 4DIGIT) / "GMT" / ...
 
 	for _, dow := range dows {
 		for _, day := range days {
@@ -98,6 +98,29 @@
 // ParseDate parses an RFC 5322 date string.
 func ParseDate(date string) (time.Time, error) {
 	dateLayoutsBuildOnce.Do(buildDateLayouts)
+	// CR and LF must match and are tolerated anywhere in the date field.
+	date = strings.ReplaceAll(date, "\r\n", "")
+	if strings.Index(date, "\r") != -1 {
+		return time.Time{}, errors.New("mail: header has a CR without LF")
+	}
+	// Re-using some addrParser methods which support obsolete text, i.e. non-printable ASCII
+	p := addrParser{date, nil}
+	p.skipSpace()
+
+	// RFC 5322: zone = (FWS ( "+" / "-" ) 4DIGIT) / obs-zone
+	// zone length is always 5 chars unless obsolete (obs-zone)
+	if ind := strings.IndexAny(p.s, "+-"); ind != -1 && len(p.s) >= ind+5 {
+		date = p.s[:ind+5]
+		p.s = p.s[ind+5:]
+	} else if ind := strings.Index(p.s, "T"); ind != -1 && len(p.s) >= ind+1 {
+		// The last letter T of the obsolete time zone is checked when no standard time zone is found.
+		// If T is misplaced, the date to parse is garbage.
+		date = p.s[:ind+1]
+		p.s = p.s[ind+1:]
+	}
+	if !p.skipCFWS() {
+		return time.Time{}, errors.New("mail: misformatted parenthetical comment")
+	}
 	for _, layout := range dateLayouts {
 		t, err := time.Parse(layout, date)
 		if err == nil {
diff --git a/src/net/mail/message_test.go b/src/net/mail/message_test.go
index 2950bc4..fbdc4f7 100644
--- a/src/net/mail/message_test.go
+++ b/src/net/mail/message_test.go
@@ -124,6 +124,151 @@
 	}
 }
 
+func TestDateParsingCFWS(t *testing.T) {
+	tests := []struct {
+		dateStr string
+		exp     time.Time
+		valid   bool
+	}{
+		// FWS-only. No date.
+		{
+			"   ",
+			// nil is not allowed
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("", -6*60*60)),
+			false,
+		},
+		// FWS is allowed before optional day of week.
+		{
+			"   Fri, 21 Nov 1997 09:55:06 -0600",
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("", -6*60*60)),
+			true,
+		},
+		{
+			"21 Nov 1997 09:55:06 -0600",
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("", -6*60*60)),
+			true,
+		},
+		{
+			"Fri 21 Nov 1997 09:55:06 -0600",
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("", -6*60*60)),
+			false, // missing ,
+		},
+		// FWS is allowed before day of month but HTAB fails.
+		{
+			"Fri,        21 Nov 1997 09:55:06 -0600",
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("", -6*60*60)),
+			true,
+		},
+		// FWS is allowed before and after year but HTAB fails.
+		{
+			"Fri, 21 Nov       1997     09:55:06 -0600",
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("", -6*60*60)),
+			true,
+		},
+		// FWS is allowed before zone but HTAB is not handled. Obsolete timezone is handled.
+		{
+			"Fri, 21 Nov 1997 09:55:06           CST",
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("CST", 0)),
+			true,
+		},
+		// FWS is allowed after date and a CRLF is already replaced.
+		{
+			"Fri, 21 Nov 1997 09:55:06           CST (no leading FWS and a trailing CRLF) \r\n",
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("CST", 0)),
+			true,
+		},
+		// CFWS is a reduced set of US-ASCII where space and accentuated are obsolete. No error.
+		{
+			"Fri, 21    Nov 1997    09:55:06 -0600 (MDT and non-US-ASCII signs éèç )",
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("", -6*60*60)),
+			true,
+		},
+		// CFWS is allowed after zone including a nested comment.
+		// Trailing FWS is allowed.
+		{
+			"Fri, 21 Nov 1997 09:55:06 -0600    \r\n (thisisa(valid)cfws)   \t ",
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("", -6*60*60)),
+			true,
+		},
+		// CRLF is incomplete and misplaced.
+		{
+			"Fri, 21 Nov 1997 \r 09:55:06 -0600    \r\n (thisisa(valid)cfws)   \t ",
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("", -6*60*60)),
+			false,
+		},
+		// CRLF is complete but misplaced. No error is returned.
+		{
+			"Fri, 21 Nov 199\r\n7  09:55:06 -0600    \r\n (thisisa(valid)cfws)   \t ",
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("", -6*60*60)),
+			true, // should be false in the strict interpretation of RFC 5322.
+		},
+		// Invalid ASCII in date.
+		{
+			"Fri, 21 Nov 1997 ù 09:55:06 -0600    \r\n (thisisa(valid)cfws)   \t ",
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("", -6*60*60)),
+			false,
+		},
+		// CFWS chars () in date.
+		{
+			"Fri, 21 Nov () 1997 09:55:06 -0600    \r\n (thisisa(valid)cfws)   \t ",
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("", -6*60*60)),
+			false,
+		},
+		// Timezone is invalid but T is found in comment.
+		{
+			"Fri, 21 Nov 1997 09:55:06 -060    \r\n (Thisisa(valid)cfws)   \t ",
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("", -6*60*60)),
+			false,
+		},
+		// Date has no month.
+		{
+			"Fri, 21  1997 09:55:06 -0600",
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("", -6*60*60)),
+			false,
+		},
+		// Invalid month : OCT iso Oct
+		{
+			"Fri, 21 OCT 1997 09:55:06 CST",
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("", -6*60*60)),
+			false,
+		},
+		// A too short time zone.
+		{
+			"Fri, 21 Nov 1997 09:55:06 -060",
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("", -6*60*60)),
+			false,
+		},
+		// A too short obsolete time zone.
+		{
+			"Fri, 21  1997 09:55:06 GT",
+			time.Date(1997, 11, 21, 9, 55, 6, 0, time.FixedZone("", -6*60*60)),
+			false,
+		},
+	}
+	for _, test := range tests {
+		hdr := Header{
+			"Date": []string{test.dateStr},
+		}
+		date, err := hdr.Date()
+		if err != nil && test.valid {
+			t.Errorf("Header(Date: %s).Date(): %v", test.dateStr, err)
+		} else if err == nil && !date.Equal(test.exp) && test.valid {
+			t.Errorf("Header(Date: %s).Date() = %+v, want %+v", test.dateStr, date, test.exp)
+		} else if err == nil && !test.valid { // an invalid expression was tested
+			t.Errorf("Header(Date: %s).Date() did not return an error but %v", test.dateStr, date)
+		}
+
+		date, err = ParseDate(test.dateStr)
+		if err != nil && test.valid {
+			t.Errorf("ParseDate(%s): %v", test.dateStr, err)
+		} else if err == nil && !test.valid { // an invalid expression was tested
+			t.Errorf("ParseDate(%s) did not return an error but %v", test.dateStr, date)
+		} else if err == nil && test.valid && !date.Equal(test.exp) {
+			t.Errorf("ParseDate(%s) = %+v, want %+v", test.dateStr, date, test.exp)
+		}
+	}
+}
+
 func TestAddressParsingError(t *testing.T) {
 	mustErrTestCases := [...]struct {
 		text        string