diff --git a/v2rayN/ServiceLib.Tests/Fmt/NaiveFmtUserInfoTests.cs b/v2rayN/ServiceLib.Tests/Fmt/NaiveFmtUserInfoTests.cs
new file mode 100644
index 00000000..6f08c279
--- /dev/null
+++ b/v2rayN/ServiceLib.Tests/Fmt/NaiveFmtUserInfoTests.cs
@@ -0,0 +1,71 @@
+namespace ServiceLib.Tests.Fmt;
+
+public class NaiveFmtUserInfoTests
+{
+    [Test]
+    [Arguments("pa:ss")]
+    [Arguments("a:b:c")]
+    [Arguments(":leading")]
+    [Arguments("trailing:")]
+    public async Task GetShareUriAndResolveConfig_PasswordOnlyWithColon_ShouldKeepPassword(string password)
+    {
+        var source = CreateNaiveProfile(string.Empty, password);
+
+        var uri = FmtHandler.GetShareUri(source);
+        await uri.Should().NotBeNull();
+
+        var resolved = FmtHandler.ResolveConfig(uri!, out var msg);
+
+        await resolved.Should().NotBeNull().Because($"uri: {uri}, msg: {msg}");
+        await resolved!.Username.Should().BeEqualTo(string.Empty);
+        await resolved.Password.Should().BeEqualTo(password);
+    }
+
+    [Test]
+    public async Task GetShareUriAndResolveConfig_UsernameAndPasswordWithColons_ShouldKeepBoth()
+    {
+        var source = CreateNaiveProfile("us:er", "pa:ss");
+
+        var uri = FmtHandler.GetShareUri(source);
+        await uri.Should().NotBeNull();
+
+        var resolved = FmtHandler.ResolveConfig(uri!, out var msg);
+
+        await resolved.Should().NotBeNull().Because($"uri: {uri}, msg: {msg}");
+        await resolved!.Username.Should().BeEqualTo("us:er");
+        await resolved.Password.Should().BeEqualTo("pa:ss");
+    }
+
+    [Test]
+    [Arguments("naive+https://what:happened@test.someone.cf:443", "what", "happened")]
+    [Arguments("naive+https://what:hap:pened@test.someone.cf:443", "what", "hap:pened")]
+    [Arguments("naive+https://wh%40t:hap%3Apened@test.someone.cf:443", "wh@t", "hap:pened")]
+    [Arguments("naive+https://pa%3Ass@test.someone.cf:443", "", "pa:ss")]
+    [Arguments("naive+quic://secret@test.someone.cf:443", "", "secret")]
+    public async Task ResolveConfig_ShouldSplitUserInfoBeforeDecoding(string shareUri, string username, string password)
+    {
+        var resolved = FmtHandler.ResolveConfig(shareUri, out var msg);
+
+        await resolved.Should().NotBeNull().Because($"uri: {shareUri}, msg: {msg}");
+        await resolved!.Username.Should().BeEqualTo(username);
+        await resolved.Password.Should().BeEqualTo(password);
+    }
+
+    private static ProfileItem CreateNaiveProfile(string username, string password)
+    {
+        var item = new ProfileItem
+        {
+            ConfigType = EConfigType.Naive,
+            Remarks = "naive demo",
+            Address = "naive.example",
+            Port = 443,
+            Username = username,
+            Password = password,
+            Network = nameof(ETransport.raw),
+            StreamSecurity = Global.None,
+        };
+        item.SetTransportExtra(new TransportExtraItem { RawHeaderType = Global.None, });
+
+        return item;
+    }
+}
diff --git a/v2rayN/ServiceLib/Handler/Fmt/NaiveFmt.cs b/v2rayN/ServiceLib/Handler/Fmt/NaiveFmt.cs
index 5349b205..e44c194c 100644
--- a/v2rayN/ServiceLib/Handler/Fmt/NaiveFmt.cs
+++ b/v2rayN/ServiceLib/Handler/Fmt/NaiveFmt.cs
@@ -30,16 +30,17 @@ public class NaiveFmt : BaseFmt
                 NaiveQuic = true,
             };
         }
-        var rawUserInfo = Utils.UrlDecode(parsedUrl.UserInfo);
+        // Split before decoding: ToUri percent-encodes a ':' inside the username or password.
+        var rawUserInfo = parsedUrl.UserInfo;
         if (rawUserInfo.Contains(':'))
         {
             var split = rawUserInfo.Split(':', 2);
-            item.Username = split[0];
-            item.Password = split[1];
+            item.Username = Utils.UrlDecode(split[0]);
+            item.Password = Utils.UrlDecode(split[1]);
         }
         else
         {
-            item.Password = rawUserInfo;
+            item.Password = Utils.UrlDecode(rawUserInfo);
         }
 
         var query = Utils.ParseQueryString(parsedUrl.Query);