diff --git a/proto/protovalidate/buf/validate/validate.proto b/proto/protovalidate/buf/validate/validate.proto
index 1153909d..3e76513e 100644
--- a/proto/protovalidate/buf/validate/validate.proto
+++ b/proto/protovalidate/buf/validate/validate.proto
@@ -3828,7 +3828,7 @@ message StringRules {
         message: "must be a valid HTTP header name"
         expression:
           "rules.well_known_regex != 1 || this == '' || this.matches(!has(rules.strict) || rules.strict ?"
-          "'^:?[0-9a-zA-Z!#$%&\\'*+-.^_|~\\x60]+$' :"
+          "'^:?[0-9a-zA-Z!#$%&\\'*+.^_|~\\x60-]+$' :"
           "'^[^\\u0000\\u000A\\u000D]+$')"
       },
       (predefined).cel = {
diff --git a/tools/internal/gen/buf/validate/validate.pb.go b/tools/internal/gen/buf/validate/validate.pb.go
index 63a735ff..d82d16fc 100644
--- a/tools/internal/gen/buf/validate/validate.pb.go
+++ b/tools/internal/gen/buf/validate/validate.pb.go
@@ -8609,7 +8609,7 @@ const file_buf_validate_validate_proto_rawDesc = "" +
 	"\x1dstring.protobuf_dot_fqn_empty\x12Uvalue is empty, which is not a valid fully-qualified Protobuf name with a leading dot\x1a%!rules.protobuf_dot_fqn || this != ''H\x00R\x0eprotobufDotFqn\x12\xac\x05\n" +
 	"\x10well_known_regex\x18\x18 \x01(\x0e2\x18.buf.validate.KnownRegexB\xe5\x04\xc2H\xe1\x04\n" +
 	"\xea\x01\n" +
-	"#string.well_known_regex.header_name\x12 must be a valid HTTP header name\x1a\xa0\x01rules.well_known_regex != 1 || this == '' || this.matches(!has(rules.strict) || rules.strict ?'^:?[0-9a-zA-Z!#$%&\\'*+-.^_|~\\x60]+$' :'^[^\\u0000\\u000A\\u000D]+$')\n" +
+	"#string.well_known_regex.header_name\x12 must be a valid HTTP header name\x1a\xa0\x01rules.well_known_regex != 1 || this == '' || this.matches(!has(rules.strict) || rules.strict ?'^:?[0-9a-zA-Z!#$%&\\'*+.^_|~\\x60-]+$' :'^[^\\u0000\\u000A\\u000D]+$')\n" +
 	"\x8d\x01\n" +
 	")string.well_known_regex.header_name_empty\x125value is empty, which is not a valid HTTP header name\x1a)rules.well_known_regex != 1 || this != ''\n" +
 	"\xe1\x01\n" +
diff --git a/tools/protovalidate-conformance/internal/cases/cases_strings.go b/tools/protovalidate-conformance/internal/cases/cases_strings.go
index 0d75bb33..af6b8174 100644
--- a/tools/protovalidate-conformance/internal/cases/cases_strings.go
+++ b/tools/protovalidate-conformance/internal/cases/cases_strings.go
@@ -1528,6 +1528,10 @@ func stringSuite() suites.Suite {
 			Message:  &cases.StringHttpHeaderName{Val: ":authority"},
 			Expected: results.Success(true),
 		},
+		"well_known_regex/header_name/strict/valid/all_chars": {
+			Message:  &cases.StringHttpHeaderName{Val: "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!#$%&'*+-.^_|~`"},
+			Expected: results.Success(true),
+		},
 		"well_known_regex/header_name/strict/valid/numbers": {
 			Message:  &cases.StringHttpHeaderName{Val: "abc-123"},
 			Expected: results.Success(true),
@@ -1570,6 +1574,16 @@ func stringSuite() suites.Suite {
 				},
 			),
 		},
+		"well_known_regex/header_name/strict/invalid/comma": {
+			Message: &cases.StringHttpHeaderName{Val: "foo,bar"},
+			Expected: results.Violations(
+				&validate.Violation{
+					Field:  results.FieldPath("val"),
+					Rule:   results.FieldPath("string.well_known_regex"),
+					RuleId: proto.String("string.well_known_regex.header_name"),
+				},
+			),
+		},
 		"well_known_regex/header_name/strict/invalid/space": {
 			Message: &cases.StringHttpHeaderName{Val: "foo bar"},
 			Expected: results.Violations(