diff --git a/quiche/http2/adapter/header_validator.cc b/quiche/http2/adapter/header_validator.cc
index 67d543a..e4874f2 100644
--- a/quiche/http2/adapter/header_validator.cc
+++ b/quiche/http2/adapter/header_validator.cc
@@ -246,6 +246,12 @@
   return false;
 }
 
+/* static */
+bool HeaderValidator::IsValidAuthority(absl::string_view authority) {
+  static const CharMap valid_chars = BuildValidCharMap(kValidAuthorityChars);
+  return AllCharsInMap(authority, valid_chars);
+}
+
 HeaderValidator::ContentLengthStatus HeaderValidator::HandleContentLength(
     absl::string_view value) {
   if (value.empty()) {
@@ -278,8 +284,7 @@
 // Returns whether `authority` contains only characters from the `host` ABNF
 // from RFC 3986 section 3.2.2.
 bool HeaderValidator::ValidateAndSetAuthority(absl::string_view authority) {
-  static const CharMap valid_chars = BuildValidCharMap(kValidAuthorityChars);
-  if (!AllCharsInMap(authority, valid_chars)) {
+  if (!IsValidAuthority(authority)) {
     return false;
   }
   if (authority_.has_value() && authority != authority_.value()) {
diff --git a/quiche/http2/adapter/header_validator.h b/quiche/http2/adapter/header_validator.h
index 096f76f..6095c7d 100644
--- a/quiche/http2/adapter/header_validator.h
+++ b/quiche/http2/adapter/header_validator.h
@@ -25,6 +25,9 @@
   // present for the given header type.
   bool FinishHeaderBlock(HeaderType type) override;
 
+  // Returns whether `authority` is valid according to RFC 3986 Section 3.2.
+  static bool IsValidAuthority(absl::string_view authority);
+
  private:
   enum ContentLengthStatus {
     CONTENT_LENGTH_OK,
diff --git a/quiche/http2/adapter/header_validator_test.cc b/quiche/http2/adapter/header_validator_test.cc
index 6e446f2..a329f12 100644
--- a/quiche/http2/adapter/header_validator_test.cc
+++ b/quiche/http2/adapter/header_validator_test.cc
@@ -150,45 +150,59 @@
   for (absl::string_view key : {":authority", "host"}) {
     // These characters should be allowed. (Not exhaustive.)
     for (const absl::string_view c : {"1", "-", "!", ":", "+", "=", ","}) {
+      const std::string value = absl::StrCat("ho", c, "st.example.com");
+      EXPECT_TRUE(HeaderValidator::IsValidAuthority(value));
+
       HeaderValidator v;
       v.StartHeaderBlock();
-      HeaderValidator::HeaderStatus status =
-          v.ValidateSingleHeader(key, absl::StrCat("ho", c, "st.example.com"));
+      HeaderValidator::HeaderStatus status = v.ValidateSingleHeader(key, value);
       EXPECT_EQ(HeaderValidator::HEADER_OK, status);
     }
     // These should not.
     for (const absl::string_view c : {"\r", "\n", "|", "\\", "`"}) {
+      const std::string value = absl::StrCat("ho", c, "st.example.com");
+      EXPECT_FALSE(HeaderValidator::IsValidAuthority(value));
+
       HeaderValidator v;
       v.StartHeaderBlock();
-      HeaderValidator::HeaderStatus status =
-          v.ValidateSingleHeader(key, absl::StrCat("ho", c, "st.example.com"));
+      HeaderValidator::HeaderStatus status = v.ValidateSingleHeader(key, value);
       EXPECT_EQ(HeaderValidator::HEADER_FIELD_INVALID, status);
     }
 
     {
       // IPv4 example
+      const std::string value = "123.45.67.89";
+      EXPECT_TRUE(HeaderValidator::IsValidAuthority(value));
+
       HeaderValidator v;
       v.StartHeaderBlock();
-      HeaderValidator::HeaderStatus status =
-          v.ValidateSingleHeader(key, "123.45.67.89");
+      HeaderValidator::HeaderStatus status = v.ValidateSingleHeader(key, value);
       EXPECT_EQ(HeaderValidator::HEADER_OK, status);
     }
 
     {
       // IPv6 examples
+      const std::string value1 = "2001:0db8:85a3:0000:0000:8a2e:0370:7334";
+      EXPECT_TRUE(HeaderValidator::IsValidAuthority(value1));
+
       HeaderValidator v;
       v.StartHeaderBlock();
-      HeaderValidator::HeaderStatus status = v.ValidateSingleHeader(
-          key, "2001:0db8:85a3:0000:0000:8a2e:0370:7334");
+      HeaderValidator::HeaderStatus status =
+          v.ValidateSingleHeader(key, value1);
       EXPECT_EQ(HeaderValidator::HEADER_OK, status);
+
+      const std::string value2 = "[::1]:80";
+      EXPECT_TRUE(HeaderValidator::IsValidAuthority(value2));
       HeaderValidator v2;
       v2.StartHeaderBlock();
-      status = v2.ValidateSingleHeader(key, "[::1]:80");
+      status = v2.ValidateSingleHeader(key, value2);
       EXPECT_EQ(HeaderValidator::HEADER_OK, status);
     }
 
     {
       // Empty field
+      EXPECT_TRUE(HeaderValidator::IsValidAuthority(""));
+
       HeaderValidator v;
       v.StartHeaderBlock();
       HeaderValidator::HeaderStatus status = v.ValidateSingleHeader(key, "");