diff --git a/controller/telegram.go b/controller/telegram.go
index b5918d8e..d51bed2b 100644
--- a/controller/telegram.go
+++ b/controller/telegram.go
@@ -4,9 +4,13 @@ import (
 	"crypto/hmac"
 	"crypto/sha256"
 	"encoding/hex"
-	"io"
+	"errors"
 	"net/http"
+	"net/url"
 	"sort"
+	"strconv"
+	"strings"
+	"time"
 
 	"github.com/QuantumNous/new-api/common"
 	"github.com/QuantumNous/new-api/model"
@@ -15,6 +19,13 @@ import (
 	"github.com/gin-gonic/gin"
 )
 
+const (
+	// The legacy Telegram widget has no nonce. Keep its signed assertion short-lived
+	// so captured callbacks cannot be reused indefinitely.
+	telegramAuthorizationMaxAge     = 5 * time.Minute
+	telegramAuthorizationFutureSkew = 2 * time.Minute
+)
+
 func TelegramBind(c *gin.Context) {
 	if !common.TelegramOAuthEnabled {
 		c.JSON(200, gin.H{
@@ -24,14 +35,15 @@ func TelegramBind(c *gin.Context) {
 		return
 	}
 	params := c.Request.URL.Query()
-	if !checkTelegramAuthorization(params, common.TelegramBotToken) {
+	telegramId, err := verifyTelegramAuthorization(params, common.TelegramBotToken, time.Now())
+	if err != nil {
+		common.SysLog("TelegramBind authorization failed: " + err.Error())
 		c.JSON(200, gin.H{
 			"message": "无效的请求",
 			"success": false,
 		})
 		return
 	}
-	telegramId := params["id"][0]
 	if model.IsTelegramIdAlreadyTaken(telegramId) {
 		c.JSON(200, gin.H{
 			"message": "该 Telegram 账户已被绑定",
@@ -78,7 +90,9 @@ func TelegramLogin(c *gin.Context) {
 		return
 	}
 	params := c.Request.URL.Query()
-	if !checkTelegramAuthorization(params, common.TelegramBotToken) {
+	telegramId, err := verifyTelegramAuthorization(params, common.TelegramBotToken, time.Now())
+	if err != nil {
+		common.SysLog("TelegramLogin authorization failed: " + err.Error())
 		c.JSON(200, gin.H{
 			"message": "无效的请求",
 			"success": false,
@@ -86,7 +100,6 @@ func TelegramLogin(c *gin.Context) {
 		return
 	}
 
-	telegramId := params["id"][0]
 	user := model.User{TelegramId: telegramId}
 	if err := user.FillUserByTelegramId(); err != nil {
 		c.JSON(200, gin.H{
@@ -98,28 +111,46 @@ func TelegramLogin(c *gin.Context) {
 	setupLogin(&user, c)
 }
 
-func checkTelegramAuthorization(params map[string][]string, token string) bool {
-	strs := []string{}
-	var hash = ""
+func verifyTelegramAuthorization(params url.Values, token string, now time.Time) (string, error) {
+	if token == "" {
+		return "", errors.New("telegram bot token is empty")
+	}
+	for _, values := range params {
+		if len(values) != 1 {
+			return "", errors.New("telegram authorization contains duplicate parameters")
+		}
+	}
+
+	telegramID := params.Get("id")
+	hash := params.Get("hash")
+	authDateText := params.Get("auth_date")
+	if telegramID == "" || hash == "" || authDateText == "" {
+		return "", errors.New("telegram authorization is incomplete")
+	}
+	authDate, err := strconv.ParseInt(authDateText, 10, 64)
+	if err != nil {
+		return "", errors.New("telegram authorization date is invalid")
+	}
+	if authDate < now.Add(-telegramAuthorizationMaxAge).Unix() ||
+		authDate > now.Add(telegramAuthorizationFutureSkew).Unix() {
+		return "", errors.New("telegram authorization has expired")
+	}
+
+	strs := make([]string, 0, len(params)-1)
 	for k, v := range params {
 		if k == "hash" {
-			hash = v[0]
 			continue
 		}
 		strs = append(strs, k+"="+v[0])
 	}
 	sort.Strings(strs)
-	var imploded = ""
-	for _, s := range strs {
-		if imploded != "" {
-			imploded += "\n"
-		}
-		imploded += s
+	secret := sha256.Sum256([]byte(token))
+	mac := hmac.New(sha256.New, secret[:])
+	_, _ = mac.Write([]byte(strings.Join(strs, "\n")))
+	providedHash, err := hex.DecodeString(hash)
+	if err != nil || !hmac.Equal(providedHash, mac.Sum(nil)) {
+		return "", errors.New("telegram authorization signature is invalid")
 	}
-	sha256hash := sha256.New()
-	io.WriteString(sha256hash, token)
-	hmachash := hmac.New(sha256.New, sha256hash.Sum(nil))
-	io.WriteString(hmachash, imploded)
-	ss := hex.EncodeToString(hmachash.Sum(nil))
-	return hash == ss
+
+	return telegramID, nil
 }
diff --git a/controller/telegram_test.go b/controller/telegram_test.go
new file mode 100644
index 00000000..5b683fb7
--- /dev/null
+++ b/controller/telegram_test.go
@@ -0,0 +1,78 @@
+package controller
+
+import (
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/hex"
+	"net/url"
+	"sort"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestVerifyTelegramAuthorization(t *testing.T) {
+	const token = "telegram-test-token"
+	now := time.Unix(1_700_000_000, 0)
+
+	tests := []struct {
+		name     string
+		authDate time.Time
+		mutate   func(url.Values)
+		wantID   string
+		wantErr  string
+	}{
+		{name: "valid", authDate: now, wantID: "123456"},
+		{name: "small future clock skew", authDate: now.Add(90 * time.Second), wantID: "123456"},
+		{name: "expired", authDate: now.Add(-telegramAuthorizationMaxAge - time.Second), wantErr: "expired"},
+		{name: "too far in future", authDate: now.Add(telegramAuthorizationFutureSkew + time.Second), wantErr: "expired"},
+		{name: "invalid signature", authDate: now, mutate: func(values url.Values) { values.Set("hash", "00") }, wantErr: "signature"},
+		{name: "duplicate parameter", authDate: now, mutate: func(values url.Values) { values["id"] = append(values["id"], "654321") }, wantErr: "duplicate"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			params := signedTelegramAuthorization(token, tt.authDate)
+			if tt.mutate != nil {
+				tt.mutate(params)
+			}
+
+			telegramID, err := verifyTelegramAuthorization(params, token, now)
+			if tt.wantErr != "" {
+				require.Error(t, err)
+				assert.ErrorContains(t, err, tt.wantErr)
+				assert.Empty(t, telegramID)
+				return
+			}
+
+			require.NoError(t, err)
+			assert.Equal(t, tt.wantID, telegramID)
+		})
+	}
+}
+
+func signedTelegramAuthorization(token string, authDate time.Time) url.Values {
+	params := url.Values{
+		"auth_date":  {strconv.FormatInt(authDate.Unix(), 10)},
+		"first_name": {"Test"},
+		"id":         {"123456"},
+	}
+	keys := make([]string, 0, len(params))
+	for key := range params {
+		keys = append(keys, key)
+	}
+	sort.Strings(keys)
+	dataCheck := make([]string, 0, len(keys))
+	for _, key := range keys {
+		dataCheck = append(dataCheck, key+"="+params.Get(key))
+	}
+	secret := sha256.Sum256([]byte(token))
+	mac := hmac.New(sha256.New, secret[:])
+	_, _ = mac.Write([]byte(strings.Join(dataCheck, "\n")))
+	params.Set("hash", hex.EncodeToString(mac.Sum(nil)))
+	return params
+}
diff --git a/controller/user.go b/controller/user.go
index 3e5293be..6316fd13 100644
--- a/controller/user.go
+++ b/controller/user.go
@@ -73,7 +73,13 @@ func Login(c *gin.Context) {
 	}
 
 	// 检查是否启用2FA
-	if model.IsTwoFAEnabled(user.Id) {
+	twoFAEnabled, err := model.IsTwoFAEnabled(user.Id)
+	if err != nil {
+		common.SysLog(fmt.Sprintf("Login failed to load 2FA status for user %d: %v", user.Id, err))
+		common.ApiErrorI18n(c, i18n.MsgDatabaseError)
+		return
+	}
+	if twoFAEnabled {
 		// 设置pending session，等待2FA验证
 		session := sessions.Default(c)
 		session.Set("pending_username", user.Username)
diff --git a/model/task_cas_test.go b/model/task_cas_test.go
index 479774cd..91ca28fc 100644
--- a/model/task_cas_test.go
+++ b/model/task_cas_test.go
@@ -38,6 +38,9 @@ func TestMain(m *testing.M) {
 		&Task{},
 		&User{},
 		&Token{},
+		&PasskeyCredential{},
+		&TwoFA{},
+		&TwoFABackupCode{},
 		&Log{},
 		&Channel{},
 		&QuotaData{},
@@ -62,8 +65,12 @@ func truncateTables(t *testing.T) {
 	t.Helper()
 	t.Cleanup(func() {
 		DB.Exec("DELETE FROM tasks")
-		DB.Exec("DELETE FROM users")
+		DB.Exec("DELETE FROM passkey_credentials")
+		DB.Exec("DELETE FROM two_fa_backup_codes")
+		DB.Exec("DELETE FROM two_fas")
 		DB.Exec("DELETE FROM tokens")
+		DB.Exec("DELETE FROM user_oauth_bindings")
+		DB.Exec("DELETE FROM users")
 		DB.Exec("DELETE FROM logs")
 		DB.Exec("DELETE FROM channels")
 		DB.Exec("DELETE FROM quota_data")
@@ -72,7 +79,6 @@ func truncateTables(t *testing.T) {
 		DB.Exec("DELETE FROM subscription_orders")
 		DB.Exec("DELETE FROM subscription_plans")
 		DB.Exec("DELETE FROM user_subscriptions")
-		DB.Exec("DELETE FROM user_oauth_bindings")
 		DB.Exec("DELETE FROM perf_metrics")
 		DB.Exec("DELETE FROM system_instances")
 		DB.Exec("DELETE FROM system_task_locks")
diff --git a/model/token.go b/model/token.go
index cb34b3ce..5d62258e 100644
--- a/model/token.go
+++ b/model/token.go
@@ -505,6 +505,13 @@ func InvalidateUserTokensCache(userId int) error {
 		Find(&tokens).Error; err != nil {
 		return err
 	}
+	return invalidateTokensCache(tokens)
+}
+
+func invalidateTokensCache(tokens []Token) error {
+	if !common.RedisEnabled {
+		return nil
+	}
 	var firstErr error
 	for _, t := range tokens {
 		if t.Key == "" {
diff --git a/model/twofa.go b/model/twofa.go
index a2d0c7e1..1887bfe5 100644
--- a/model/twofa.go
+++ b/model/twofa.go
@@ -54,12 +54,12 @@ func GetTwoFAByUserId(userId int) (*TwoFA, error) {
 }
 
 // IsTwoFAEnabled 检查用户是否启用了2FA
-func IsTwoFAEnabled(userId int) bool {
+func IsTwoFAEnabled(userId int) (bool, error) {
 	twoFA, err := GetTwoFAByUserId(userId)
-	if err != nil || twoFA == nil {
-		return false
+	if err != nil {
+		return false, err
 	}
-	return twoFA.IsEnabled
+	return twoFA != nil && twoFA.IsEnabled, nil
 }
 
 // CreateTwoFA 创建2FA设置
@@ -120,15 +120,50 @@ func (t *TwoFA) ResetFailedAttempts() error {
 
 // IncrementFailedAttempts 增加失败尝试次数
 func (t *TwoFA) IncrementFailedAttempts() error {
-	t.FailedAttempts++
-
-	// 检查是否需要锁定
-	if t.FailedAttempts >= common.MaxFailAttempts {
-		lockUntil := time.Now().Add(time.Duration(common.LockoutDuration) * time.Second)
-		t.LockedUntil = &lockUntil
+	if t.Id == 0 {
+		return errors.New("2FA记录ID不能为空")
 	}
 
-	return t.Update()
+	const maxUpdateRetries = 5
+	for range maxUpdateRetries {
+		var current TwoFA
+		if err := DB.Select("id", "failed_attempts", "locked_until").First(&current, t.Id).Error; err != nil {
+			return err
+		}
+
+		now := time.Now()
+		if current.LockedUntil != nil && now.Before(*current.LockedUntil) {
+			t.FailedAttempts = current.FailedAttempts
+			t.LockedUntil = current.LockedUntil
+			return nil
+		}
+
+		nextFailedAttempts := current.FailedAttempts + 1
+		nextLockedUntil := current.LockedUntil
+		if nextFailedAttempts >= common.MaxFailAttempts {
+			lockUntil := now.Add(time.Duration(common.LockoutDuration) * time.Second)
+			nextLockedUntil = &lockUntil
+		}
+
+		result := DB.Model(&TwoFA{}).
+			Where("id = ? AND failed_attempts = ? AND (locked_until IS NULL OR locked_until <= ?)", current.Id, current.FailedAttempts, now).
+			Updates(map[string]interface{}{
+				"failed_attempts": nextFailedAttempts,
+				"locked_until":    nextLockedUntil,
+			})
+		if result.Error != nil {
+			return result.Error
+		}
+		if result.RowsAffected == 0 {
+			continue
+		}
+
+		t.FailedAttempts = nextFailedAttempts
+		t.LockedUntil = nextLockedUntil
+		return nil
+	}
+
+	return errors.New("更新2FA失败次数冲突，请重试")
 }
 
 // IsLocked 检查账户是否被锁定
@@ -186,16 +221,17 @@ func ValidateBackupCode(userId int, code string) (bool, error) {
 	// 验证备用码
 	for _, bc := range backupCodes {
 		if common.ValidatePasswordAndHash(normalizedCode, bc.CodeHash) {
-			// 标记为已使用
 			now := time.Now()
-			bc.IsUsed = true
-			bc.UsedAt = &now
-
-			if err := DB.Save(&bc).Error; err != nil {
-				return false, err
+			result := DB.Model(&TwoFABackupCode{}).
+				Where("id = ? AND is_used = ?", bc.Id, false).
+				Updates(map[string]interface{}{
+					"is_used": true,
+					"used_at": now,
+				})
+			if result.Error != nil {
+				return false, result.Error
 			}
-
-			return true, nil
+			return result.RowsAffected == 1, nil
 		}
 	}
 
diff --git a/model/user.go b/model/user.go
index 08ffabcc..03eb589e 100644
--- a/model/user.go
+++ b/model/user.go
@@ -423,12 +423,8 @@ func HardDeleteUserById(id int) error {
 	if id == 0 {
 		return errors.New("id 为空！")
 	}
-	return DB.Transaction(func(tx *gorm.DB) error {
-		if err := deleteUserOAuthBindingsByUserId(tx, id); err != nil {
-			return err
-		}
-		return tx.Unscoped().Delete(&User{}, "id = ?", id).Error
-	})
+	user := User{Id: id}
+	return user.HardDelete()
 }
 
 func inviteUser(inviterId int) (err error) {
@@ -754,12 +750,42 @@ func (user *User) HardDelete() error {
 	if user.Id == 0 {
 		return errors.New("id 为空！")
 	}
-	return DB.Transaction(func(tx *gorm.DB) error {
-		if err := deleteUserOAuthBindingsByUserId(tx, user.Id); err != nil {
+	var tokens []Token
+	err := DB.Transaction(func(tx *gorm.DB) error {
+		if common.RedisEnabled {
+			if err := tx.Unscoped().Select("id", commonKeyCol).Where("user_id = ?", user.Id).Find(&tokens).Error; err != nil {
+				return err
+			}
+		}
+		if err := deleteUserAuthenticationData(tx, user.Id); err != nil {
 			return err
 		}
 		return tx.Unscoped().Delete(user).Error
 	})
+	if err != nil {
+		return err
+	}
+	if err := invalidateTokensCache(tokens); err != nil {
+		common.SysError(fmt.Sprintf("failed to invalidate token cache after hard deleting user %d: %v", user.Id, err))
+	}
+	if err := invalidateUserCache(user.Id); err != nil {
+		common.SysError(fmt.Sprintf("failed to invalidate user cache after hard deleting user %d: %v", user.Id, err))
+	}
+	return nil
+}
+
+func deleteUserAuthenticationData(tx *gorm.DB, userId int) error {
+	for _, authenticationData := range []any{
+		&TwoFABackupCode{},
+		&TwoFA{},
+		&PasskeyCredential{},
+		&Token{},
+	} {
+		if err := tx.Unscoped().Where("user_id = ?", userId).Delete(authenticationData).Error; err != nil {
+			return err
+		}
+	}
+	return deleteUserOAuthBindingsByUserId(tx, userId)
 }
 
 // ValidateAndFill check password & user status
diff --git a/model/user_authentication_test.go b/model/user_authentication_test.go
new file mode 100644
index 00000000..c285e023
--- /dev/null
+++ b/model/user_authentication_test.go
@@ -0,0 +1,130 @@
+package model
+
+import (
+	"context"
+	"errors"
+	"net"
+	"sync"
+	"sync/atomic"
+	"testing"
+
+	"github.com/QuantumNous/new-api/common"
+	"github.com/go-redis/redis/v8"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestHardDeleteUserPurgesAuthenticationDataWhenRedisFails(t *testing.T) {
+	truncateTables(t)
+
+	user := User{Username: "hard-delete-user", Password: "password"}
+	require.NoError(t, DB.Create(&user).Error)
+	require.NoError(t, DB.Create(&Token{UserId: user.Id, Key: "hard-delete-token"}).Error)
+	require.NoError(t, DB.Create(&TwoFA{UserId: user.Id, Secret: "secret", IsEnabled: true}).Error)
+	require.NoError(t, DB.Create(&TwoFABackupCode{UserId: user.Id, CodeHash: "hash"}).Error)
+	require.NoError(t, DB.Create(&PasskeyCredential{UserID: user.Id, CredentialID: "credential", PublicKey: "public-key"}).Error)
+	require.NoError(t, DB.Create(&UserOAuthBinding{UserId: user.Id, ProviderId: 1, ProviderUserId: "provider-user"}).Error)
+
+	oldRedisEnabled, oldRDB := common.RedisEnabled, common.RDB
+	common.RedisEnabled = true
+	var cacheInvalidatedAfterCommit atomic.Bool
+	common.RDB = redis.NewClient(&redis.Options{
+		Dialer: func(context.Context, string, string) (net.Conn, error) {
+			var count int64
+			if err := DB.Unscoped().Model(&User{}).Where("id = ?", user.Id).Count(&count).Error; err == nil && count == 0 {
+				cacheInvalidatedAfterCommit.Store(true)
+			}
+			return nil, errors.New("forced redis failure")
+		},
+		MaxRetries: -1,
+	})
+	t.Cleanup(func() {
+		_ = common.RDB.Close()
+		common.RedisEnabled, common.RDB = oldRedisEnabled, oldRDB
+	})
+
+	require.NoError(t, HardDeleteUserById(user.Id))
+	assert.True(t, cacheInvalidatedAfterCommit.Load())
+
+	var count int64
+	require.NoError(t, DB.Unscoped().Model(&User{}).Where("id = ?", user.Id).Count(&count).Error)
+	assert.Zero(t, count)
+	for _, record := range []any{
+		&Token{},
+		&TwoFA{},
+		&TwoFABackupCode{},
+		&PasskeyCredential{},
+		&UserOAuthBinding{},
+	} {
+		require.NoError(t, DB.Unscoped().Model(record).Where("user_id = ?", user.Id).Count(&count).Error)
+		assert.Zero(t, count)
+	}
+}
+
+func TestIncrementFailedAttemptsCountsConcurrentFailures(t *testing.T) {
+	truncateTables(t)
+
+	user := User{Username: "twofa-cas-user", Password: "password"}
+	require.NoError(t, DB.Create(&user).Error)
+	twoFA := TwoFA{UserId: user.Id, Secret: "secret", IsEnabled: true}
+	require.NoError(t, DB.Create(&twoFA).Error)
+
+	const attempts = 4
+	errs := make(chan error, attempts)
+	var wg sync.WaitGroup
+	for range attempts {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			errs <- (&TwoFA{Id: twoFA.Id}).IncrementFailedAttempts()
+		}()
+	}
+	wg.Wait()
+	close(errs)
+	for err := range errs {
+		require.NoError(t, err)
+	}
+
+	var reloaded TwoFA
+	require.NoError(t, DB.First(&reloaded, twoFA.Id).Error)
+	assert.Equal(t, attempts, reloaded.FailedAttempts)
+}
+
+func TestValidateBackupCodeCanOnlySucceedOnce(t *testing.T) {
+	truncateTables(t)
+
+	const code = "ABCD-1234"
+	require.NoError(t, CreateBackupCodes(123, []string{code}))
+
+	const attempts = 2
+	results := make(chan bool, attempts)
+	errs := make(chan error, attempts)
+	var wg sync.WaitGroup
+	for range attempts {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			valid, err := ValidateBackupCode(123, code)
+			results <- valid
+			errs <- err
+		}()
+	}
+	wg.Wait()
+	close(results)
+	close(errs)
+
+	for err := range errs {
+		require.NoError(t, err)
+	}
+	wins := 0
+	for valid := range results {
+		if valid {
+			wins++
+		}
+	}
+	assert.Equal(t, 1, wins)
+
+	remaining, err := GetUnusedBackupCodeCount(123)
+	require.NoError(t, err)
+	assert.Zero(t, remaining)
+}