diff --git a/src/Server/ZB.MOM.WW.OtOpcUa.Security/Endpoints/AuthEndpoints.cs b/src/Server/ZB.MOM.WW.OtOpcUa.Security/Endpoints/AuthEndpoints.cs
index 6212a79d..b5ff6f95 100644
--- a/src/Server/ZB.MOM.WW.OtOpcUa.Security/Endpoints/AuthEndpoints.cs
+++ b/src/Server/ZB.MOM.WW.OtOpcUa.Security/Endpoints/AuthEndpoints.cs
@@ -6,6 +6,9 @@ using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Routing;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using ZB.MOM.WW.OtOpcUa.Configuration.Services;
 using ZB.MOM.WW.OtOpcUa.Security.Jwt;
 using ZB.MOM.WW.OtOpcUa.Security.Ldap;
 
@@ -40,6 +43,7 @@ public static class AuthEndpoints
     private static async Task<IResult> LoginAsync(
         HttpContext http,
         ILdapAuthService ldap,
+        ILdapGroupRoleMappingService roleMappings,
         CancellationToken ct)
     {
         var isForm = http.Request.HasFormContentType;
@@ -83,13 +87,27 @@ public static class AuthEndpoints
             return Results.Redirect("/login" + qs);
         }
 
+        IReadOnlyList<string> roles = result.Roles;
+        try
+        {
+            var dbRows = await roleMappings.GetByGroupsAsync(result.Groups, ct);
+            roles = RoleMapper.Merge(result.Roles, dbRows);
+        }
+        catch (Exception ex)
+        {
+            // A DB hiccup must never block sign-in — fall back to the appsettings baseline roles.
+            http.RequestServices.GetService<ILoggerFactory>()?
+                .CreateLogger("ZB.MOM.WW.OtOpcUa.Security.AuthEndpoints")
+                .LogWarning(ex, "DB role-map lookup failed for {User}; using appsettings baseline roles", username);
+        }
+
         var claims = new List<Claim>
         {
             new(ClaimTypes.NameIdentifier, result.Username ?? username),
             new(JwtTokenService.UsernameClaimType, result.Username ?? username),
             new(JwtTokenService.DisplayNameClaimType, result.DisplayName ?? username),
         };
-        foreach (var role in result.Roles)
+        foreach (var role in roles)
             claims.Add(new Claim(ClaimTypes.Role, role));
 
         var identity = new ClaimsIdentity(claims, CookieAuthenticationDefaults.AuthenticationScheme);
diff --git a/tests/Server/ZB.MOM.WW.OtOpcUa.Security.Tests/AuthEndpointsIntegrationTests.cs b/tests/Server/ZB.MOM.WW.OtOpcUa.Security.Tests/AuthEndpointsIntegrationTests.cs
index 59d893de..3e84cf4d 100644
--- a/tests/Server/ZB.MOM.WW.OtOpcUa.Security.Tests/AuthEndpointsIntegrationTests.cs
+++ b/tests/Server/ZB.MOM.WW.OtOpcUa.Security.Tests/AuthEndpointsIntegrationTests.cs
@@ -12,6 +12,9 @@ using Microsoft.Extensions.Hosting;
 using Shouldly;
 using Xunit;
 using ZB.MOM.WW.OtOpcUa.Configuration;
+using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
+using ZB.MOM.WW.OtOpcUa.Configuration.Services;
 using ZB.MOM.WW.OtOpcUa.Security.Endpoints;
 using ZB.MOM.WW.OtOpcUa.Security.Ldap;
 
@@ -29,6 +32,7 @@ public sealed class AuthEndpointsIntegrationTests : IAsyncLifetime
 {
     private IHost _host = null!;
     private TestServer _server = null!;
+    private readonly StubLdapGroupRoleMappingService _roleMappings = new();
 
     private static CancellationToken Ct => TestContext.Current.CancellationToken;
 
@@ -58,6 +62,10 @@ public sealed class AuthEndpointsIntegrationTests : IAsyncLifetime
                         }).Build();
                     services.AddOtOpcUaAuth(configuration);
                     services.AddSingleton<ILdapAuthService, StubLdapAuthService>();
+                    // The login handler now resolves the DB role-map service via DI to merge
+                    // DB-backed grants on top of the appsettings baseline. Register the stub so
+                    // the minimal-API handler can be constructed; tests drive its rows.
+                    services.AddSingleton<ILdapGroupRoleMappingService>(_roleMappings);
                 });
                 web.Configure(app =>
                 {
@@ -174,6 +182,79 @@ public sealed class AuthEndpointsIntegrationTests : IAsyncLifetime
         token!.Split('.').Length.ShouldBe(3);
     }
 
+    /// <summary>A system-wide DB row for a group the user holds grants an extra role on top of
+    /// the appsettings baseline; the merged role surfaces in the issued JWT's Role claims.</summary>
+    [Fact]
+    public async Task Login_merges_db_role_grant_into_claims()
+    {
+        // StubLdapAuthService returns Groups ["ReadOnly"], baseline Roles ["ConfigViewer"].
+        // A system-wide row maps "ReadOnly" → FleetAdmin, so the merged set is both.
+        _roleMappings.Rows.Add(new LdapGroupRoleMapping
+        {
+            Id = Guid.NewGuid(),
+            LdapGroup = "ReadOnly",
+            Role = AdminRole.FleetAdmin,
+            IsSystemWide = true,
+            ClusterId = null,
+        });
+
+        var client = NewClient();
+        var loginResponse = await client.PostAsJsonAsync("/auth/login",
+            new AuthEndpoints.LoginRequest("alice", "valid-password"), Ct);
+        loginResponse.EnsureSuccessStatusCode();
+
+        var tokenReq = new HttpRequestMessage(HttpMethod.Post, "/auth/token");
+        AttachCookies(tokenReq, loginResponse);
+        var tokenResp = await client.SendAsync(tokenReq, Ct);
+        tokenResp.StatusCode.ShouldBe(HttpStatusCode.OK);
+
+        var payload = await tokenResp.Content.ReadFromJsonAsync<JsonElement>(Ct);
+        var roles = JwtRoleClaims(payload.GetProperty("token").GetString()!);
+        roles.ShouldContain("ConfigViewer"); // appsettings baseline preserved
+        roles.ShouldContain("FleetAdmin");   // DB grant merged in
+    }
+
+    /// <summary>When the DB role-map lookup throws, sign-in still succeeds with the appsettings
+    /// baseline roles — a DB hiccup must never block login.</summary>
+    [Fact]
+    public async Task Login_when_db_role_map_throws_falls_back_to_baseline_roles()
+    {
+        _roleMappings.Throws = true;
+
+        var client = NewClient();
+        var loginResponse = await client.PostAsJsonAsync("/auth/login",
+            new AuthEndpoints.LoginRequest("alice", "valid-password"), Ct);
+
+        // Login proceeds despite the simulated DB outage.
+        loginResponse.StatusCode.ShouldBe(HttpStatusCode.NoContent);
+
+        var tokenReq = new HttpRequestMessage(HttpMethod.Post, "/auth/token");
+        AttachCookies(tokenReq, loginResponse);
+        var tokenResp = await client.SendAsync(tokenReq, Ct);
+        tokenResp.StatusCode.ShouldBe(HttpStatusCode.OK);
+
+        var payload = await tokenResp.Content.ReadFromJsonAsync<JsonElement>(Ct);
+        var roles = JwtRoleClaims(payload.GetProperty("token").GetString()!);
+        roles.ShouldContain("ConfigViewer"); // baseline still present
+    }
+
+    /// <summary>Extracts the "Role" claim values from a JWT's payload segment.</summary>
+    private static IReadOnlyList<string> JwtRoleClaims(string jwt)
+    {
+        var payloadSegment = jwt.Split('.')[1];
+        var padded = payloadSegment.Replace('-', '+').Replace('_', '/');
+        switch (padded.Length % 4)
+        {
+            case 2: padded += "=="; break;
+            case 3: padded += "="; break;
+        }
+        var json = JsonDocument.Parse(Convert.FromBase64String(padded));
+        if (!json.RootElement.TryGetProperty("Role", out var roleProp)) return [];
+        return roleProp.ValueKind == JsonValueKind.Array
+            ? [.. roleProp.EnumerateArray().Select(e => e.GetString()!)]
+            : [roleProp.GetString()!];
+    }
+
     /// <summary>Tests that logout clears the cookie.</summary>
     [Fact]
     public async Task Logout_clears_the_cookie()
@@ -260,4 +341,38 @@ public sealed class AuthEndpointsIntegrationTests : IAsyncLifetime
                 Error: "Invalid username or password"));
         }
     }
+
+    /// <summary>
+    /// In-memory stub for the DB-backed group→role mapping service. Tests seed <see cref="Rows"/>
+    /// and the login handler merges any system-wide row whose group the user holds. Set
+    /// <see cref="Throws"/> to simulate a DB outage and exercise the baseline-roles fallback.
+    /// </summary>
+    private sealed class StubLdapGroupRoleMappingService : ILdapGroupRoleMappingService
+    {
+        public List<LdapGroupRoleMapping> Rows { get; } = [];
+        public bool Throws { get; set; }
+
+        /// <summary>Returns seeded rows whose group matches one of <paramref name="ldapGroups"/>.</summary>
+        public Task<IReadOnlyList<LdapGroupRoleMapping>> GetByGroupsAsync(
+            IEnumerable<string> ldapGroups, CancellationToken cancellationToken)
+        {
+            if (Throws) throw new InvalidOperationException("simulated DB outage");
+            var groups = new HashSet<string>(ldapGroups, StringComparer.OrdinalIgnoreCase);
+            IReadOnlyList<LdapGroupRoleMapping> matched =
+                [.. Rows.Where(r => groups.Contains(r.LdapGroup))];
+            return Task.FromResult(matched);
+        }
+
+        /// <summary>Not exercised by these tests.</summary>
+        public Task<IReadOnlyList<LdapGroupRoleMapping>> ListAllAsync(CancellationToken cancellationToken) =>
+            throw new NotSupportedException();
+
+        /// <summary>Not exercised by these tests.</summary>
+        public Task<LdapGroupRoleMapping> CreateAsync(LdapGroupRoleMapping row, CancellationToken cancellationToken) =>
+            throw new NotSupportedException();
+
+        /// <summary>Not exercised by these tests.</summary>
+        public Task DeleteAsync(Guid id, CancellationToken cancellationToken) =>
+            throw new NotSupportedException();
+    }
 }