diff --git a/docs/DEVIATIONS.md b/docs/DEVIATIONS.md
index 7deb4c5..18f97af 100644
--- a/docs/DEVIATIONS.md
+++ b/docs/DEVIATIONS.md
@@ -1718,3 +1718,13 @@ issue #3 未关闭，`feat/fix-3-downlink-deadlock` 未合入 `main`。下面是
    - 原因：原先 12 项备注写着未穷尽仍标通过，交付说明写成「通过 23」。  
    - 备选方案：为每个未测子项补验收用例（本波不做，避免为变绿放松断言）。  
    - 影响：汇总改为通过 19、部分通过 4（F03/F08/F21/F22）、失败 0。F19 仍引用仓库内 SDK 清单、本波不重跑。
+
+### 复审修复 R3-07
+
+1. **客户端建群事务内复核创建者**  
+   - 日期：2026-09-30  
+   - 原条款：Gitea #71。`group.Create` 在 `Queue.Do` 里直接 `insertMemberTx` 群主，不跑 `endpointCheckTx`；停用/删除与建群抢在事务外对话密码窗口时，可插入已停用甚至刚删除的 `owner_id`。  
+   - 实际做法：`Create` 同一写事务里，插入群与群主成员之前对 `actorID` 做与 `createAdmin` 相同的 `endpointCheckTx`；已停用 `endpoint_disabled`，不存在 `invalid_target`，且不插入群。不改 `emit`、不改迁移编号。  
+   - 原因：成员侧已有事务内复核，群主侧缺对称校验，竞态会留下非法群主。  
+   - 备选方案：事务外再查一次创建者（否决，无法覆盖密码窗口与写事务之间的竞态）。  
+   - 影响：创建者在进入写事务前被停用/删除时建群失败且无新群行；与后台建群错误码对齐。
diff --git a/internal/app/group/app.go b/internal/app/group/app.go
index 92537a5..6418ef9 100644
--- a/internal/app/group/app.go
+++ b/internal/app/group/app.go
@@ -147,6 +147,15 @@ func (a *App) Create(ctx context.Context, actorID string, req *protocol.GroupCre
 
 	var inserted []string
 	err := a.db.Queue.Do(ctx, func(tx *sql.Tx) error {
+		if e := endpointCheckTx(tx, actorID); e != nil {
+			if protoCode(e) == protocol.CodeInvalidTarget {
+				return errCode(protocol.CodeInvalidTarget, "owner not found")
+			}
+			if protoCode(e) == protocol.CodeEndpointDisabled {
+				return errCode(protocol.CodeEndpointDisabled, "owner disabled")
+			}
+			return e
+		}
 		var exists int
 		qErr := tx.QueryRow(`SELECT 1 FROM groups WHERE id = ?`, gid).Scan(&exists)
 		if qErr == nil {
diff --git a/internal/app/group/group_test.go b/internal/app/group/group_test.go
index 0fc916d..94101f4 100644
--- a/internal/app/group/group_test.go
+++ b/internal/app/group/group_test.go
@@ -604,6 +604,106 @@ func TestU02CreateDedupesMembers(t *testing.T) {
 	}
 }
 
+// raceTalk 在对话密码校验成功后执行一次 mutate，模拟事务外密码窗口里创建者被停用/删除。
+type raceTalk struct {
+	inner  group.TalkGate
+	mutate func()
+	once   sync.Once
+}
+
+func (r *raceTalk) CheckTalkPasswordForJoin(ctx context.Context, actorID, targetID, talkPassword, remoteIP string) error {
+	err := r.inner.CheckTalkPasswordForJoin(ctx, actorID, targetID, talkPassword, remoteIP)
+	if err == nil && r.mutate != nil {
+		r.once.Do(r.mutate)
+	}
+	return err
+}
+
+func TestR307CreateRejectsActorDisabledOrDeletedBeforeWrite(t *testing.T) {
+	t.Parallel()
+	cases := []struct {
+		name string
+		code string
+		mutate func(ctx context.Context, t *testing.T, idApp *identity.App, db *store.DB)
+	}{
+		{
+			name: "disabled",
+			code: protocol.CodeEndpointDisabled,
+			mutate: func(ctx context.Context, t *testing.T, idApp *identity.App, _ *store.DB) {
+				t.Helper()
+				if err := idApp.Disable(ctx, "alice"); err != nil {
+					t.Fatal(err)
+				}
+			},
+		},
+		{
+			name: "deleted",
+			code: protocol.CodeInvalidTarget,
+			mutate: func(ctx context.Context, t *testing.T, idApp *identity.App, _ *store.DB) {
+				t.Helper()
+				if err := idApp.Delete(ctx, "alice"); err != nil {
+					t.Fatal(err)
+				}
+			},
+		},
+	}
+	for _, tc := range cases {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+			db, err := store.Open(filepath.Join(t.TempDir(), "data"), "FULL")
+			if err != nil {
+				t.Fatal(err)
+			}
+			t.Cleanup(func() { _ = db.Close() })
+			fixed := time.UnixMilli(1_700_000_000_000)
+			locks := auth.NewLoginLocks()
+			idApp := identity.New(identity.Config{
+				DB: db, Hash: auth.NewStubHashPool(), Locks: locks,
+				Sessions: auth.NewSessionTokens(),
+				Now:      func() time.Time { return fixed },
+			})
+			gate := &raceTalk{inner: idApp}
+			gApp := group.New(group.Config{
+				DB: db, Talk: gate, MaxGroupMembers: 1000,
+				Now: func() time.Time { return fixed }, DefaultRemoteIP: "1.1.1.1",
+			})
+			ctx := context.Background()
+			insertEP(t, db, "alice", 1)
+			insertEP(t, db, "bob", 1)
+			if err := idApp.SelfSetTalkPassword(ctx, "bob", "secret"); err != nil {
+				t.Fatal(err)
+			}
+			gate.mutate = func() { tc.mutate(ctx, t, idApp, db) }
+
+			var before int
+			if qErr := db.Read.QueryRow(`SELECT COUNT(*) FROM groups`).Scan(&before); qErr != nil {
+				t.Fatal(qErr)
+			}
+			_, err = gApp.Create(ctx, "alice", &protocol.GroupCreate{
+				V: protocol.Version, Type: protocol.TypeGroupCreate, RID: "1",
+				ID: "g_r307_" + tc.name, Name: "竞态群",
+				Members: []protocol.GroupMemberIn{{ID: "bob", TalkPassword: "secret"}},
+			})
+			if protoCode(err) != tc.code {
+				t.Fatalf("want %s got %v", tc.code, err)
+			}
+			var after int
+			if qErr := db.Read.QueryRow(`SELECT COUNT(*) FROM groups`).Scan(&after); qErr != nil {
+				t.Fatal(qErr)
+			}
+			if after != before {
+				t.Fatalf("groups leaked: before=%d after=%d", before, after)
+			}
+			var exists int
+			qErr := db.Read.QueryRow(`SELECT 1 FROM groups WHERE id = ?`, "g_r307_"+tc.name).Scan(&exists)
+			if !errors.Is(qErr, sql.ErrNoRows) {
+				t.Fatalf("expected no group row, got exists=%d err=%v", exists, qErr)
+			}
+		})
+	}
+}
+
 func TestU02AdminCreateOwnerMustExistAndEnabled(t *testing.T) {
 	t.Parallel()
 	gApp, _, _, db, down := setup(t)