diff --git a/packages/i18n/src/locales/en_US.ts b/packages/i18n/src/locales/en_US.ts
index a1b85647c1..090fbe28ae 100644
--- a/packages/i18n/src/locales/en_US.ts
+++ b/packages/i18n/src/locales/en_US.ts
@@ -70,7 +70,8 @@ const translations: Catalog = {
       }
     },
     'uri-generator': {
-      'no-host-port': 'If a full URI is provided, you cannot also specify --host or --port'
+      'no-host-port': 'If a full URI is provided, you cannot also specify --host or --port',
+      'invalid-host': 'The --host argument contains an invalid character'
     }
   },
   'service-provider-browser': {},
diff --git a/packages/service-provider-core/src/uri-generator.spec.ts b/packages/service-provider-core/src/uri-generator.spec.ts
index 22bccb587e..9d4789bf4f 100644
--- a/packages/service-provider-core/src/uri-generator.spec.ts
+++ b/packages/service-provider-core/src/uri-generator.spec.ts
@@ -292,4 +292,20 @@ describe('uri-generator.generate-uri', () => {
       expect.fail('expected error');
     });
   });
+
+  context('when the --host option contains invalid characters', () => {
+    const options = { host: 'a,b,c' };
+
+    it('returns the uri', () => {
+      try {
+        generateUri(options);
+      } catch (e) {
+        expect(e.message).to.contain('The --host argument contains an invalid character: ,');
+        expect(e).to.be.instanceOf(MongoshInvalidInputError);
+        expect(e.code).to.equal(CommonErrors.InvalidArgument);
+        return;
+      }
+      expect.fail('expected error');
+    });
+  });
 });
diff --git a/packages/service-provider-core/src/uri-generator.ts b/packages/service-provider-core/src/uri-generator.ts
index 395a3f7ef9..f80d98101e 100644
--- a/packages/service-provider-core/src/uri-generator.ts
+++ b/packages/service-provider-core/src/uri-generator.ts
@@ -41,17 +41,36 @@ const DEFAULT_PORT = '27017';
  */
 const CONFLICT = 'cli-repl.uri-generator.no-host-port';
 
+/**
+ * Invalid host message.
+ */
+const INVALID_HOST = 'cli-repl.uri-generator.invalid-host';
+
 /**
  * Validate conflicts in the options.
  *
  * @param {CliOptions} options - The options.
  */
-function validateConflicts(options: CliOptions): any {
+function validateConflicts(options: CliOptions): void {
   if (options.host || options.port) {
     throw new MongoshInvalidInputError(i18n.__(CONFLICT), CommonErrors.InvalidArgument);
   }
 }
 
+/**
+ * Perform basic validation of the --host option.
+ *
+ * @param {string} host - The value of the --host option.
+ */
+function validateHost(host: string): void {
+  const invalidCharacter = host.match(/[^a-zA-Z0-9.:\[\]-]/);
+  if (invalidCharacter) {
+    throw new MongoshInvalidInputError(
+      i18n.__(INVALID_HOST) + ': ' + invalidCharacter[0],
+      CommonErrors.InvalidArgument);
+  }
+}
+
 /**
  * Generate the host from the options or default.
  *
@@ -61,6 +80,7 @@ function validateConflicts(options: CliOptions): any {
  */
 function generateHost(options: CliOptions): string {
   if (options.host) {
+    validateHost(options.host);
     if (options.host.includes(':')) {
       return options.host.split(':')[0];
     }
@@ -78,6 +98,7 @@ function generateHost(options: CliOptions): string {
  */
 function generatePort(options: CliOptions): string {
   if (options.host && options.host.includes(':')) {
+    validateHost(options.host);
     const port = options.host.split(':')[1];
     if (!options.port || options.port === port) {
       return port;