diff --git a/src/System Application/Test/Agent/src/SDK/AgentMessageTest.Codeunit.al b/src/System Application/Test/Agent/src/SDK/AgentMessageTest.Codeunit.al
index 01c20f6c474..6cda705cf98 100644
--- a/src/System Application/Test/Agent/src/SDK/AgentMessageTest.Codeunit.al	
+++ b/src/System Application/Test/Agent/src/SDK/AgentMessageTest.Codeunit.al	
@@ -1329,6 +1329,63 @@ codeunit 133963 "Agent Message Test"
         Assert.AreEqual('last-file.txt', LastAttachment."File Name", 'Last attachment file name should match');
     end;
 
+    [Test]
+    procedure SanitizeMessagePreservesBasicFormatting()
+    var
+        AgentTaskMsgBuilderImpl: Codeunit "Agent Task Msg. Builder Impl.";
+        Body: Text;
+        SanitizedBody: Text;
+    begin
+        // [SCENARIO] Agent message sanitization preserves readable formatting and encoded text without active content.
+
+        // [GIVEN] An HTML message body containing formatting, styling, and an event handler.
+        Body := '<p style="color:red" onclick="alert()">Hello <b>world</b><br>4 &lt; 5</p>';
+
+        // [WHEN] The agent message body is sanitized.
+        SanitizedBody := AgentTaskMsgBuilderImpl.SanitizeMessage(Body);
+
+        // [THEN] Formatting and encoded text survive, while styling and the event handler are removed.
+        Assert.AreEqual('<p>Hello <b>world</b><br>4 &lt; 5</p>', SanitizedBody, 'Agent messages must retain basic formatting and encoded text without styling or event handlers.');
+    end;
+
+    [Test]
+    procedure SanitizeMessageRemovesMathmlIntegrationPoints()
+    var
+        AgentTaskMsgBuilderImpl: Codeunit "Agent Task Msg. Builder Impl.";
+        Body: Text;
+        SanitizedBody: Text;
+    begin
+        // [SCENARIO] Sanitized agent messages exclude foreign integration-point content using the HTML encoding.
+
+        // [GIVEN] A safe paragraph followed by a MathML HTML integration-point payload.
+        Body := '<p>Safe</p><math><annotation-xml encoding="text/html"><title><a encoding="</title><img src=x onerror=alert()>"></annotation-xml></math>';
+
+        // [WHEN] The agent message body is sanitized.
+        SanitizedBody := AgentTaskMsgBuilderImpl.SanitizeMessage(Body);
+
+        // [THEN] Only the safe paragraph remains.
+        Assert.AreEqual('<p>Safe</p>', SanitizedBody, 'Foreign HTML integration points and their contents must not survive agent message sanitization.');
+    end;
+
+    [Test]
+    procedure SanitizeMessageRemovesXhtmlMathmlIntegrationPoints()
+    var
+        AgentTaskMsgBuilderImpl: Codeunit "Agent Task Msg. Builder Impl.";
+        Body: Text;
+        SanitizedBody: Text;
+    begin
+        // [SCENARIO] Sanitized agent messages exclude foreign integration-point content using the XHTML encoding.
+
+        // [GIVEN] A safe paragraph followed by a MathML XHTML integration-point payload.
+        Body := '<p>Safe</p><math><annotation-xml encoding="application/xhtml+xml"><title><a encoding="</title><img src=x onerror=alert()>"></annotation-xml></math>';
+
+        // [WHEN] The XHTML-encoded payload is sanitized.
+        SanitizedBody := AgentTaskMsgBuilderImpl.SanitizeMessage(Body);
+
+        // [THEN] Only the safe paragraph remains.
+        Assert.AreEqual('<p>Safe</p>', SanitizedBody, 'The XHTML encoding must receive the same sanitization policy.');
+    end;
+
     [Test]
     procedure ContentTypeFromFilenameForKnownExtensions()
     var
diff --git a/src/System Application/Test/Email/src/EmailMessageUnitTest.Codeunit.al b/src/System Application/Test/Email/src/EmailMessageUnitTest.Codeunit.al
index 0c6020f4874..8c15d2d3d63 100644
--- a/src/System Application/Test/Email/src/EmailMessageUnitTest.Codeunit.al	
+++ b/src/System Application/Test/Email/src/EmailMessageUnitTest.Codeunit.al	
@@ -77,6 +77,105 @@ codeunit 134689 "Email Message Unit Test"
         Assert.IsTrue(Message.Attachments_Next() = 0, 'No attachments were expected');
     end;
 
+    [Test]
+    [TransactionModel(TransactionModel::AutoRollback)]
+    procedure CreateMessageWithSanitizationPreservesBasicFormatting()
+    var
+        Message: Codeunit "Email Message";
+    begin
+        // [SCENARIO] Sanitized HTML email retains readable formatting and encoded text without active content.
+
+        // [GIVEN] An email editor and HTML containing formatting, styling, and an event handler.
+        PermissionsMock.Set('Email Edit');
+
+        // [WHEN] The HTML message is created with sanitization enabled.
+        Message.Create('recipient@test.com', 'Test subject', '<p style="color:red" onclick="alert()">Hello <b>world</b><br>4 &lt; 5</p>', true, true);
+
+        // [THEN] Formatting and encoded text survive, while styling and the event handler are removed.
+        Assert.AreEqual('<p>Hello <b>world</b><br>4 &lt; 5</p>', Message.GetBody(), 'Sanitization must preserve basic formatting and encoded text but remove styling and event handlers.');
+    end;
+
+    [Test]
+    [TransactionModel(TransactionModel::AutoRollback)]
+    procedure CreateMessageWithSanitizationRemovesMathmlIntegrationPoints()
+    var
+        Message: Codeunit "Email Message";
+        Body: Text;
+    begin
+        // [SCENARIO] Sanitized email excludes foreign integration-point content using the HTML encoding.
+
+        // [GIVEN] An email editor and a safe paragraph followed by a MathML HTML integration-point payload.
+        PermissionsMock.Set('Email Edit');
+        Body := '<p>Safe</p><math><annotation-xml encoding="text/html"><title><a encoding="</title><img src=x onerror=alert()>"></annotation-xml></math>';
+
+        // [WHEN] The HTML message is created with sanitization enabled.
+        Message.Create('recipient@test.com', 'Test subject', Body, true, true);
+
+        // [THEN] Only the safe paragraph remains.
+        Assert.AreEqual('<p>Safe</p>', Message.GetBody(), 'Foreign HTML integration points and their contents must not survive email sanitization.');
+    end;
+
+    [Test]
+    [TransactionModel(TransactionModel::AutoRollback)]
+    procedure CreateMessageWithSanitizationRemovesXhtmlMathmlIntegrationPoints()
+    var
+        Message: Codeunit "Email Message";
+        Body: Text;
+    begin
+        // [SCENARIO] Sanitized email excludes foreign integration-point content using the XHTML encoding.
+
+        // [GIVEN] An email editor and a safe paragraph followed by a MathML XHTML integration-point payload.
+        PermissionsMock.Set('Email Edit');
+        Body := '<p>Safe</p><math><annotation-xml encoding="application/xhtml+xml"><title><a encoding="</title><img src=x onerror=alert()>"></annotation-xml></math>';
+
+        // [WHEN] The XHTML-encoded payload is sanitized during message creation.
+        Message.Create('recipient@test.com', 'Test subject', Body, true, true);
+
+        // [THEN] Only the safe paragraph remains.
+        Assert.AreEqual('<p>Safe</p>', Message.GetBody(), 'The XHTML encoding must receive the same sanitization policy.');
+    end;
+
+    [Test]
+    [TransactionModel(TransactionModel::AutoRollback)]
+    procedure CreatePlainTextMessageDoesNotApplyHtmlSanitization()
+    var
+        Message: Codeunit "Email Message";
+        Body: Text;
+    begin
+        // [SCENARIO] Plain-text email treats markup as literal content even when sanitization is requested.
+
+        // [GIVEN] An email editor and literal text containing markup and an ampersand.
+        PermissionsMock.Set('Email Edit');
+        Body := '<p>Literal text</p> & <b>more text</b>';
+
+        // [WHEN] A plain-text message is created with the sanitization option enabled.
+        Message.Create('recipient@test.com', 'Test subject', Body, false, true);
+
+        // [THEN] The body is unchanged and the message remains plain text.
+        Assert.AreEqual(Body, Message.GetBody(), 'The sanitization option must not alter a plain-text message.');
+        Assert.IsFalse(Message.IsBodyHTMLFormatted(), 'The message must remain plain text.');
+    end;
+
+    [Test]
+    [TransactionModel(TransactionModel::AutoRollback)]
+    procedure CreateHtmlMessageCanKeepSanitizationDisabled()
+    var
+        Message: Codeunit "Email Message";
+        Body: Text;
+    begin
+        // [SCENARIO] Email callers can retain HTML styling by explicitly disabling sanitization.
+
+        // [GIVEN] An email editor and an HTML body with styling.
+        PermissionsMock.Set('Email Edit');
+        Body := '<p style="color:red">Formatted text</p>';
+
+        // [WHEN] The HTML message is created with sanitization disabled.
+        Message.Create('recipient@test.com', 'Test subject', Body, true, false);
+
+        // [THEN] The HTML body, including its styling, is preserved.
+        Assert.AreEqual(Body, Message.GetBody(), 'The dependency upgrade must not implicitly enable the optional sanitizer.');
+    end;
+
     [Test]
     [TransactionModel(TransactionModel::AutoRollback)]
     procedure CreateMessageWithCCAndBCCTest()