diff --git a/src/core/core_auth_session.erl b/src/core/core_auth_session.erl
index 2b9da03..864d26e 100755
--- a/src/core/core_auth_session.erl
+++ b/src/core/core_auth_session.erl
@@ -5,6 +5,7 @@
 %%%-------------------------------------------------------------------
 -module(core_auth_session).
 -include("records.hrl").
+-include_lib("stdlib/include/ms_transform.hrl").
 -export([create/3, get/1, rotate/2, revoke/1, revoke_family/1, revoke_all_for_subject/2]).
 
 -define(REFRESH_TTL_SECONDS, 30 * 24 * 3600).
@@ -32,9 +33,14 @@ create(SubjectId, SubjectType, ClientType) ->
     created_at   = Now,
     updated_at   = Now
   },
-  mnesia:dirty_write(Session),
-  inc_counter(SubjectType),
-  {ok, Session}.
+  %% Transaction ensures atomic write of the new session record.
+  case mnesia:transaction(fun() -> mnesia:write(Session) end) of
+    {atomic, ok} ->
+      inc_counter(SubjectType),
+      {ok, Session};
+    {aborted, Reason} ->
+      {error, Reason}
+  end.
 
 %%%-------------------------------------------------------------------
 %%% @doc Получить сессию по идентификатору.
@@ -56,11 +62,19 @@ get(SessionId) ->
   {ok, NewJti :: binary(), #auth_session{}} |
   {error, not_found | expired | revoked | reuse_detected}.
 rotate(SessionId, PresentedJti) ->
-  case mnesia:dirty_read({auth_session, SessionId}) of
-    [Session] ->
-      rotate_session(Session, PresentedJti);
-    [] ->
-      {error, not_found}
+  %% Transaction prevents concurrent rotate from racing on the same session
+  %% (e.g. two clients presenting the same jti simultaneously).
+  F = fun() ->
+    case mnesia:read(auth_session, SessionId, write) of
+      [Session] ->
+        rotate_session(Session, PresentedJti);
+      [] ->
+        {error, not_found}
+    end
+  end,
+  case mnesia:transaction(F) of
+    {atomic, Result} -> Result;
+    {aborted, _Reason} -> {error, transaction_failed}
   end.
 
 %%%-------------------------------------------------------------------
@@ -69,60 +83,98 @@ rotate(SessionId, PresentedJti) ->
 %%%-------------------------------------------------------------------
 -spec revoke(SessionId :: binary()) -> ok | {error, not_found}.
 revoke(SessionId) ->
-  case mnesia:dirty_read({auth_session, SessionId}) of
-    [Session] when Session#auth_session.revoked =:= true ->
+  %% Transaction ensures the read-then-write revocation is atomic.
+  F = fun() ->
+    case mnesia:read(auth_session, SessionId, write) of
+      [Session] when Session#auth_session.revoked =:= true ->
+        ok;
+      [Session] ->
+        Now = calendar:universal_time(),
+        mnesia:write(Session#auth_session{revoked = true, updated_at = Now}),
+        {revoked, Session#auth_session.subject_type};
+      [] ->
+        {error, not_found}
+    end
+  end,
+  case mnesia:transaction(F) of
+    {atomic, ok} -> ok;
+    {atomic, {revoked, SubjectType}} ->
+      dec_counter(SubjectType),
       ok;
-    [Session] ->
-      Now = calendar:universal_time(),
-      mnesia:dirty_write(Session#auth_session{revoked = true, updated_at = Now}),
-      dec_counter(Session#auth_session.subject_type),
-      ok;
-    [] ->
-      {error, not_found}
+    {atomic, {error, _} = Err} -> Err;
+    {aborted, _Reason} -> {error, transaction_failed}
   end.
 
 %%%-------------------------------------------------------------------
 %%% @doc Отозвать все сессии семейства (reuse attack / принудительный logout).
 %%% @end
 %%%-------------------------------------------------------------------
--spec revoke_family(FamilyId :: binary()) -> ok.
+-spec revoke_family(FamilyId :: binary()) -> ok | {error, transaction_failed}.
 revoke_family(FamilyId) ->
-  Sessions = mnesia:dirty_index_read(auth_session, FamilyId, #auth_session.family_id),
-  Now = calendar:universal_time(),
-  lists:foreach(fun(Session) ->
-    case Session#auth_session.revoked of
-      true -> ok;
-      false ->
-        mnesia:dirty_write(Session#auth_session{revoked = true, updated_at = Now}),
-        dec_counter(Session#auth_session.subject_type)
-    end
-                end, Sessions),
-  ok.
+  %% Transaction ensures all sessions in the family are revoked atomically,
+  %% preventing partial revocation under concurrent access.
+  F = fun() ->
+    Sessions = mnesia:index_read(auth_session, FamilyId, #auth_session.family_id),
+    Now = calendar:universal_time(),
+    RevokedTypes = lists:filtermap(fun(Session) ->
+      case Session#auth_session.revoked of
+        true -> false;
+        false ->
+          mnesia:write(Session#auth_session{revoked = true, updated_at = Now}),
+          {true, Session#auth_session.subject_type}
+      end
+    end, Sessions),
+    RevokedTypes
+  end,
+  case mnesia:transaction(F) of
+    {atomic, Types} ->
+      %% Decrement counters outside the transaction
+      lists:foreach(fun dec_counter/1, Types),
+      ok;
+    {aborted, _Reason} ->
+      {error, transaction_failed}
+  end.
 
 %%%-------------------------------------------------------------------
 %%% @doc Отозвать все сессии субъекта (например после сброса пароля).
 %%% @end
 %%%-------------------------------------------------------------------
--spec revoke_all_for_subject(SubjectId :: binary(), SubjectType :: user | admin) -> ok.
+-spec revoke_all_for_subject(SubjectId :: binary(), SubjectType :: user | admin) ->
+  ok | {error, transaction_failed}.
 revoke_all_for_subject(SubjectId, SubjectType) ->
-  Sessions = mnesia:dirty_match_object(#auth_session{subject_id = SubjectId, _ = '_'}),
-  Now = calendar:universal_time(),
-  lists:foreach(fun(Session) ->
-    case Session#auth_session.subject_type =:= SubjectType andalso
-         Session#auth_session.revoked =:= false of
-      true ->
-        mnesia:dirty_write(Session#auth_session{revoked = true, updated_at = Now}),
-        dec_counter(Session#auth_session.subject_type);
-      false ->
-        ok
-    end
-                end, Sessions),
-  ok.
+  %% Transaction ensures all matching sessions are revoked atomically.
+  F = fun() ->
+    MS = ets:fun2ms(fun(#auth_session{subject_id = Sid} = S)
+                         when Sid =:= SubjectId -> S end),
+    Sessions = mnesia:select(auth_session, MS, write),
+    Now = calendar:universal_time(),
+    Count = lists:foldl(fun(Session, Acc) ->
+      case Session#auth_session.subject_type =:= SubjectType andalso
+           Session#auth_session.revoked =:= false of
+        true ->
+          mnesia:write(Session#auth_session{revoked = true, updated_at = Now}),
+          Acc + 1;
+        false ->
+          Acc
+      end
+    end, 0, Sessions),
+    Count
+  end,
+  case mnesia:transaction(F) of
+    {atomic, Count} ->
+      %% Decrement counters outside the transaction
+      lists:foreach(fun(_) -> dec_counter(SubjectType) end, lists:seq(1, Count)),
+      ok;
+    {aborted, _Reason} ->
+      {error, transaction_failed}
+  end.
 
 %%%===================================================================
 %%% Internal
 %%%===================================================================
 
+%% NOTE: Called inside a mnesia:transaction/1 from rotate/2.
+%% Uses mnesia:read/3 and mnesia:write/1 (not dirty_ variants).
 rotate_session(Session, PresentedJti) ->
   case Session#auth_session.revoked of
     true ->
@@ -140,7 +192,7 @@ rotate_session(Session, PresentedJti) ->
                 current_jti = NewJti,
                 updated_at  = Now
               },
-              mnesia:dirty_write(Updated),
+              mnesia:write(Updated),
               {ok, NewJti, Updated};
             false ->
               {error, reuse_detected}