🚦 fix: ERR_ERL_INVALID_IP_ADDRESS and IPv6 Key Collisions in IP Rate Limiters (#12319)

* fix: Add removePorts keyGenerator to all IP-based rate limiters

Six IP-based rate limiters are missing the `keyGenerator: removePorts`
option that is already used by the auth-related limiters (login,
register, resetPassword, verifyEmail). Without it, reverse proxies that
include ports in X-Forwarded-For headers cause
ERR_ERL_INVALID_IP_ADDRESS errors from express-rate-limit.

Fixes #12318

* fix: make removePorts IPv6-safe to prevent rate-limit key collisions

The original regex `/:\d+[^:]*$/` treated the last colon-delimited
segment of bare IPv6 addresses as a port, mangling valid IPs
(e.g. `::1` → `::`, `2001:db8::1` → `2001:db8::`). Distinct IPv6
clients could collapse into the same rate-limit bucket.

Use `net.isIP()` as a fast path for already-valid IPs, then match
bracketed IPv6+port and IPv4+port explicitly. Bare IPv6 addresses
are now returned unchanged.

Also fixes pre-existing property ordering inconsistency in
ttsLimiters.js userLimiterOptions (keyGenerator before store).

* refactor: move removePorts to packages/api as TypeScript, fix import order

- Move removePorts implementation to packages/api/src/utils/removePorts.ts
  with proper Express Request typing
- Reduce api/server/utils/removePorts.js to a thin re-export from
  @librechat/api for backward compatibility
- Consolidate removePorts import with limiterCache from @librechat/api
  in all 6 limiter files, fixing import order (package imports shortest
  to longest, local imports longest to shortest)
- Remove narrating inline comments per code style guidelines

---------

Co-authored-by: Danny Avila <danny@librechat.ai>

api/cache/banViolation.js

@@ -1,8 +1,7 @@
 const { logger } = require('@librechat/data-schemas');
-const { isEnabled, math } = require('@librechat/api');
 const { ViolationTypes } = require('librechat-data-provider');
+const { isEnabled, math, removePorts } = require('@librechat/api');
 const { deleteAllUserSessions } = require('~/models');
-const { removePorts } = require('~/server/utils');
 const getLogStores = require('./getLogStores');
 
 const { BAN_VIOLATIONS, BAN_INTERVAL } = process.env ?? {};

api/server/middleware/checkBan.js

@@ -1,11 +1,10 @@
 const { Keyv } = require('keyv');
 const uap = require('ua-parser-js');
 const { logger } = require('@librechat/data-schemas');
-const { isEnabled, keyvMongo } = require('@librechat/api');
 const { ViolationTypes } = require('librechat-data-provider');
-const { removePorts } = require('~/server/utils');
-const denyRequest = require('./denyRequest');
+const { isEnabled, keyvMongo, removePorts } = require('@librechat/api');
 const { getLogStores } = require('~/cache');
+const denyRequest = require('./denyRequest');
 const { findUser } = require('~/models');
 
 const banCache = new Keyv({ store: keyvMongo, namespace: ViolationTypes.BAN, ttl: 0 });

api/server/middleware/limiters/forkLimiters.js

@@ -1,6 +1,6 @@
 const rateLimit = require('express-rate-limit');
-const { limiterCache } = require('@librechat/api');
 const { ViolationTypes } = require('librechat-data-provider');
+const { limiterCache, removePorts } = require('@librechat/api');
 const logViolation = require('~/cache/logViolation');
 
 const getEnvironmentVariables = () => {
@@ -59,6 +59,7 @@ const createForkLimiters = () => {
     windowMs: forkIpWindowMs,
     max: forkIpMax,
     handler: createForkHandler(),
+    keyGenerator: removePorts,
     store: limiterCache('fork_ip_limiter'),
   };
   const userLimiterOptions = {

api/server/middleware/limiters/importLimiters.js

@@ -1,6 +1,6 @@
 const rateLimit = require('express-rate-limit');
-const { limiterCache } = require('@librechat/api');
 const { ViolationTypes } = require('librechat-data-provider');
+const { limiterCache, removePorts } = require('@librechat/api');
 const logViolation = require('~/cache/logViolation');
 
 const getEnvironmentVariables = () => {
@@ -60,6 +60,7 @@ const createImportLimiters = () => {
     windowMs: importIpWindowMs,
     max: importIpMax,
     handler: createImportHandler(),
+    keyGenerator: removePorts,
     store: limiterCache('import_ip_limiter'),
   };
   const userLimiterOptions = {
@@ -67,7 +68,7 @@ const createImportLimiters = () => {
     max: importUserMax,
     handler: createImportHandler(false),
     keyGenerator: function (req) {
-      return req.user?.id; // Use the user ID or NULL if not available
+      return req.user?.id;
     },
     store: limiterCache('import_user_limiter'),
   };

api/server/middleware/limiters/loginLimiter.js

@@ -1,7 +1,6 @@
 const rateLimit = require('express-rate-limit');
-const { limiterCache } = require('@librechat/api');
 const { ViolationTypes } = require('librechat-data-provider');
-const { removePorts } = require('~/server/utils');
+const { limiterCache, removePorts } = require('@librechat/api');
 const { logViolation } = require('~/cache');
 
 const { LOGIN_WINDOW = 5, LOGIN_MAX = 7, LOGIN_VIOLATION_SCORE: score } = process.env;

api/server/middleware/limiters/messageLimiters.js

@@ -1,6 +1,6 @@
 const rateLimit = require('express-rate-limit');
-const { limiterCache } = require('@librechat/api');
 const { ViolationTypes } = require('librechat-data-provider');
+const { limiterCache, removePorts } = require('@librechat/api');
 const denyRequest = require('~/server/middleware/denyRequest');
 const { logViolation } = require('~/cache');
 
@@ -50,6 +50,7 @@ const ipLimiterOptions = {
   windowMs: ipWindowMs,
   max: ipMax,
   handler: createHandler(),
+  keyGenerator: removePorts,
   store: limiterCache('message_ip_limiter'),
 };
 
@@ -58,7 +59,7 @@ const userLimiterOptions = {
   max: userMax,
   handler: createHandler(false),
   keyGenerator: function (req) {
-    return req.user?.id; // Use the user ID or NULL if not available
+    return req.user?.id;
   },
   store: limiterCache('message_user_limiter'),
 };

api/server/middleware/limiters/registerLimiter.js

@@ -1,7 +1,6 @@
 const rateLimit = require('express-rate-limit');
-const { limiterCache } = require('@librechat/api');
 const { ViolationTypes } = require('librechat-data-provider');
-const { removePorts } = require('~/server/utils');
+const { limiterCache, removePorts } = require('@librechat/api');
 const { logViolation } = require('~/cache');
 
 const { REGISTER_WINDOW = 60, REGISTER_MAX = 5, REGISTRATION_VIOLATION_SCORE: score } = process.env;

api/server/middleware/limiters/resetPasswordLimiter.js

@@ -1,7 +1,6 @@
 const rateLimit = require('express-rate-limit');
-const { limiterCache } = require('@librechat/api');
 const { ViolationTypes } = require('librechat-data-provider');
-const { removePorts } = require('~/server/utils');
+const { limiterCache, removePorts } = require('@librechat/api');
 const { logViolation } = require('~/cache');
 
 const {

api/server/middleware/limiters/sttLimiters.js

@@ -1,6 +1,6 @@
 const rateLimit = require('express-rate-limit');
-const { limiterCache } = require('@librechat/api');
 const { ViolationTypes } = require('librechat-data-provider');
+const { limiterCache, removePorts } = require('@librechat/api');
 const logViolation = require('~/cache/logViolation');
 
 const getEnvironmentVariables = () => {
@@ -54,6 +54,7 @@ const createSTTLimiters = () => {
     windowMs: sttIpWindowMs,
     max: sttIpMax,
     handler: createSTTHandler(),
+    keyGenerator: removePorts,
     store: limiterCache('stt_ip_limiter'),
   };
 
@@ -62,7 +63,7 @@ const createSTTLimiters = () => {
     max: sttUserMax,
     handler: createSTTHandler(false),
     keyGenerator: function (req) {
-      return req.user?.id; // Use the user ID or NULL if not available
+      return req.user?.id;
     },
     store: limiterCache('stt_user_limiter'),
   };

api/server/middleware/limiters/ttsLimiters.js

@@ -1,6 +1,6 @@
 const rateLimit = require('express-rate-limit');
-const { limiterCache } = require('@librechat/api');
 const { ViolationTypes } = require('librechat-data-provider');
+const { limiterCache, removePorts } = require('@librechat/api');
 const logViolation = require('~/cache/logViolation');
 
 const getEnvironmentVariables = () => {
@@ -54,6 +54,7 @@ const createTTSLimiters = () => {
     windowMs: ttsIpWindowMs,
     max: ttsIpMax,
     handler: createTTSHandler(),
+    keyGenerator: removePorts,
     store: limiterCache('tts_ip_limiter'),
   };
 
@@ -61,10 +62,10 @@ const createTTSLimiters = () => {
     windowMs: ttsUserWindowMs,
     max: ttsUserMax,
     handler: createTTSHandler(false),
-    store: limiterCache('tts_user_limiter'),
     keyGenerator: function (req) {
-      return req.user?.id; // Use the user ID or NULL if not available
+      return req.user?.id;
     },
+    store: limiterCache('tts_user_limiter'),
   };
 
   const ttsIpLimiter = rateLimit(ipLimiterOptions);

api/server/middleware/limiters/uploadLimiters.js

@@ -1,6 +1,6 @@
 const rateLimit = require('express-rate-limit');
-const { limiterCache } = require('@librechat/api');
 const { ViolationTypes } = require('librechat-data-provider');
+const { limiterCache, removePorts } = require('@librechat/api');
 const logViolation = require('~/cache/logViolation');
 
 const getEnvironmentVariables = () => {
@@ -60,6 +60,7 @@ const createFileLimiters = () => {
     windowMs: fileUploadIpWindowMs,
     max: fileUploadIpMax,
     handler: createFileUploadHandler(),
+    keyGenerator: removePorts,
     store: limiterCache('file_upload_ip_limiter'),
   };
 
@@ -68,7 +69,7 @@ const createFileLimiters = () => {
     max: fileUploadUserMax,
     handler: createFileUploadHandler(false),
     keyGenerator: function (req) {
-      return req.user?.id; // Use the user ID or NULL if not available
+      return req.user?.id;
     },
     store: limiterCache('file_upload_user_limiter'),
   };

api/server/middleware/limiters/verifyEmailLimiter.js

@@ -1,7 +1,6 @@
 const rateLimit = require('express-rate-limit');
-const { limiterCache } = require('@librechat/api');
 const { ViolationTypes } = require('librechat-data-provider');
-const { removePorts } = require('~/server/utils');
+const { limiterCache, removePorts } = require('@librechat/api');
 const { logViolation } = require('~/cache');
 
 const {

api/server/utils/index.js

@@ -1,4 +1,3 @@
-const removePorts = require('./removePorts');
 const handleText = require('./handleText');
 const sendEmail = require('./sendEmail');
 const queue = require('./queue');
@@ -6,7 +5,6 @@ const files = require('./files');
 
 module.exports = {
   ...handleText,
-  removePorts,
   sendEmail,
   ...files,
   ...queue,

api/server/utils/removePorts.js

@@ -1 +0,0 @@
-module.exports = (req) => req?.ip?.replace(/:\d+[^:]*$/, '');

packages/api/src/utils/index.ts

@@ -18,6 +18,7 @@ export * from './math';
 export * from './oidc';
 export * from './openid';
 export * from './promise';
+export * from './ports';
 export * from './sanitizeTitle';
 export * from './tempChatRetention';
 export * from './text';

packages/api/src/utils/ports.spec.ts

@@ -0,0 +1,98 @@
+import type { Request } from 'express';
+import { removePorts } from './ports';
+
+const req = (ip: string | undefined): Request => ({ ip }) as Request;
+
+describe('removePorts', () => {
+  describe('bare IPv4 (no port)', () => {
+    test('returns a standard private IP unchanged', () => {
+      expect(removePorts(req('192.168.1.1'))).toBe('192.168.1.1');
+    });
+
+    test('returns a public IP unchanged', () => {
+      expect(removePorts(req('149.154.20.46'))).toBe('149.154.20.46');
+    });
+
+    test('returns loopback unchanged', () => {
+      expect(removePorts(req('127.0.0.1'))).toBe('127.0.0.1');
+    });
+  });
+
+  describe('IPv4 with port (the primary bug scenario)', () => {
+    test('strips port from a private IP', () => {
+      expect(removePorts(req('192.168.1.1:8080'))).toBe('192.168.1.1');
+    });
+
+    test('strips port from the IP in the original issue report', () => {
+      expect(removePorts(req('149.154.20.46:48198'))).toBe('149.154.20.46');
+    });
+
+    test('strips a low port number', () => {
+      expect(removePorts(req('10.0.0.1:80'))).toBe('10.0.0.1');
+    });
+
+    test('strips a high port number', () => {
+      expect(removePorts(req('10.0.0.1:65535'))).toBe('10.0.0.1');
+    });
+  });
+
+  describe('bare IPv6 (no port)', () => {
+    test('returns loopback unchanged', () => {
+      expect(removePorts(req('::1'))).toBe('::1');
+    });
+
+    test('returns a full address unchanged', () => {
+      expect(removePorts(req('2001:db8::1'))).toBe('2001:db8::1');
+    });
+
+    test('returns an IPv4-mapped IPv6 address unchanged', () => {
+      expect(removePorts(req('::ffff:192.168.1.1'))).toBe('::ffff:192.168.1.1');
+    });
+
+    test('returns a fully expanded IPv6 unchanged', () => {
+      expect(removePorts(req('2001:0db8:85a3:0000:0000:8a2e:0370:7334'))).toBe(
+        '2001:0db8:85a3:0000:0000:8a2e:0370:7334',
+      );
+    });
+  });
+
+  describe('bracketed IPv6 with port', () => {
+    test('extracts loopback from brackets with port', () => {
+      expect(removePorts(req('[::1]:8080'))).toBe('::1');
+    });
+
+    test('extracts a full address from brackets with port', () => {
+      expect(removePorts(req('[2001:db8::1]:443'))).toBe('2001:db8::1');
+    });
+
+    test('extracts address from brackets without port', () => {
+      expect(removePorts(req('[::1]'))).toBe('::1');
+    });
+  });
+
+  describe('falsy / missing ip', () => {
+    test('returns undefined when ip is undefined', () => {
+      expect(removePorts(req(undefined))).toBeUndefined();
+    });
+
+    test('returns undefined when ip is empty string', () => {
+      expect(removePorts({ ip: '' } as Request)).toBe('');
+    });
+
+    test('returns undefined when req is null', () => {
+      expect(removePorts(null as unknown as Request)).toBeUndefined();
+    });
+  });
+
+  describe('IPv4-mapped IPv6 with port', () => {
+    test('strips port from an IPv4-mapped IPv6 address', () => {
+      expect(removePorts(req('::ffff:1.2.3.4:8080'))).toBe('::ffff:1.2.3.4');
+    });
+  });
+
+  describe('unrecognized formats fall through unchanged', () => {
+    test('returns garbage input unchanged', () => {
+      expect(removePorts(req('not-an-ip'))).toBe('not-an-ip');
+    });
+  });
+});

packages/api/src/utils/ports.ts

@@ -0,0 +1,38 @@
+import type { Request } from 'express';
+
+/** Strips port suffix from req.ip for use as a rate-limiter key (IPv4 and IPv6-safe) */
+export function removePorts(req: Request): string | undefined {
+  const ip = req?.ip;
+  if (!ip) {
+    return ip;
+  }
+
+  if (ip.charCodeAt(0) === 91) {
+    const close = ip.indexOf(']');
+    return close > 0 ? ip.slice(1, close) : ip;
+  }
+
+  const lastColon = ip.lastIndexOf(':');
+  if (lastColon === -1) {
+    return ip;
+  }
+
+  if (ip.indexOf('.') !== -1 && hasOnlyDigitsAfter(ip, lastColon + 1)) {
+    return ip.slice(0, lastColon);
+  }
+
+  return ip;
+}
+
+function hasOnlyDigitsAfter(str: string, start: number): boolean {
+  if (start >= str.length) {
+    return false;
+  }
+  for (let i = start; i < str.length; i++) {
+    const c = str.charCodeAt(i);
+    if (c < 48 || c > 57) {
+      return false;
+    }
+  }
+  return true;
+}