diff --git a/.changeset/patch-sanitize-core-info-logging.md b/.changeset/patch-sanitize-core-info-logging.md
new file mode 100644
index 00000000000..2032f482479
--- /dev/null
+++ b/.changeset/patch-sanitize-core-info-logging.md
@@ -0,0 +1,5 @@
+---
+"gh-aw": patch
+---
+
+Introduce `sanitized_logging.cjs` wrappers (`safeInfo`, `safeDebug`, `safeWarning`, `safeError`) and apply them to previously vulnerable `core.info()` calls so user-controlled strings can't inject workflow commands.
diff --git a/actions/setup/js/display_file_helpers.cjs b/actions/setup/js/display_file_helpers.cjs
index cf96906de89..6c73144b702 100644
--- a/actions/setup/js/display_file_helpers.cjs
+++ b/actions/setup/js/display_file_helpers.cjs
@@ -9,6 +9,7 @@
  */
 
 const fs = require("fs");
+const { safeInfo } = require("./sanitized_logging.cjs");
 
 /**
  * Display a single file's content in a collapsible group
@@ -56,7 +57,7 @@ function displayFileContent(filePath, fileName, maxBytes = 64 * 1024) {
     core.startGroup(`${fileName} (${stats.size} bytes)`);
     const lines = contentToDisplay.split("\n");
     for (const line of lines) {
-      core.info(line);
+      safeInfo(line);
     }
     if (wasTruncated) {
       core.info(`...`);
diff --git a/actions/setup/js/sanitized_logging.cjs b/actions/setup/js/sanitized_logging.cjs
new file mode 100644
index 00000000000..103094ce7f0
--- /dev/null
+++ b/actions/setup/js/sanitized_logging.cjs
@@ -0,0 +1,71 @@
+// @ts-check
+/// <reference types="@actions/github-script" />
+
+/**
+ * Sanitized Logging Helpers
+ *
+ * This module provides safe logging functions that neutralize GitHub Actions
+ * workflow commands (::command::) at the start of lines to prevent workflow
+ * command injection when logging user-generated content.
+ *
+ * GitHub Actions interprets lines starting with "::" as workflow commands.
+ * For example: "::set-output name=x::value" or "::error::message"
+ *
+ * When logging user-controlled strings, these must be sanitized to prevent
+ * injection attacks where malicious input could trigger unintended workflow commands.
+ */
+
+/**
+ * Neutralizes GitHub Actions workflow commands by replacing line-start "::"
+ * @param {string} message - The message to neutralize
+ * @returns {string} The neutralized message
+ */
+function neutralizeWorkflowCommands(message) {
+  if (typeof message !== "string") {
+    return message;
+  }
+
+  // Replace "::" at the start of any line with ": :" (space inserted)
+  // The 'm' flag makes ^ match at the start of each line
+  return message.replace(/^::/gm, ": :");
+}
+
+/**
+ * Safe wrapper for core.info that neutralizes workflow commands
+ * @param {string} message - The message to log
+ */
+function safeInfo(message) {
+  core.info(neutralizeWorkflowCommands(message));
+}
+
+/**
+ * Safe wrapper for core.debug that neutralizes workflow commands
+ * @param {string} message - The message to log
+ */
+function safeDebug(message) {
+  core.debug(neutralizeWorkflowCommands(message));
+}
+
+/**
+ * Safe wrapper for core.warning that neutralizes workflow commands
+ * @param {string} message - The message to log
+ */
+function safeWarning(message) {
+  core.warning(neutralizeWorkflowCommands(message));
+}
+
+/**
+ * Safe wrapper for core.error that neutralizes workflow commands
+ * @param {string} message - The message to log
+ */
+function safeError(message) {
+  core.error(neutralizeWorkflowCommands(message));
+}
+
+module.exports = {
+  neutralizeWorkflowCommands,
+  safeInfo,
+  safeDebug,
+  safeWarning,
+  safeError,
+};
diff --git a/actions/setup/js/sanitized_logging.test.cjs b/actions/setup/js/sanitized_logging.test.cjs
new file mode 100644
index 00000000000..3eb30815283
--- /dev/null
+++ b/actions/setup/js/sanitized_logging.test.cjs
@@ -0,0 +1,202 @@
+// @ts-check
+const { neutralizeWorkflowCommands, safeInfo, safeDebug, safeWarning, safeError } = require("./sanitized_logging.cjs");
+
+// Mock core object
+global.core = {
+  info: vi.fn(),
+  debug: vi.fn(),
+  warning: vi.fn(),
+  error: vi.fn(),
+};
+
+describe("sanitized_logging", () => {
+  beforeEach(() => {
+    // Reset mocks before each test
+    vi.clearAllMocks();
+  });
+
+  describe("neutralizeWorkflowCommands", () => {
+    it("should neutralize workflow commands at the start of a line", () => {
+      const input = "::set-output name=test::value";
+      const expected = ": :set-output name=test::value";
+      expect(neutralizeWorkflowCommands(input)).toBe(expected);
+    });
+
+    it("should neutralize multiple workflow commands on different lines", () => {
+      const input = "::error::Something failed\n::warning::Be careful\n::debug::Details here";
+      const expected = ": :error::Something failed\n: :warning::Be careful\n: :debug::Details here";
+      expect(neutralizeWorkflowCommands(input)).toBe(expected);
+    });
+
+    it("should not neutralize :: in the middle of a line", () => {
+      const input = "This has :: in the middle";
+      expect(neutralizeWorkflowCommands(input)).toBe(input);
+    });
+
+    it("should not neutralize :: that is not at line start", () => {
+      const input = "namespace::function";
+      expect(neutralizeWorkflowCommands(input)).toBe(input);
+    });
+
+    it("should handle :: in various positions correctly", () => {
+      const input = "Time 12:30 PM, ratio 3:1, IPv6 ::1, namespace::function";
+      expect(neutralizeWorkflowCommands(input)).toBe(input);
+    });
+
+    it("should neutralize workflow command after newline", () => {
+      const input = "Normal text\n::set-output name=x::y";
+      const expected = "Normal text\n: :set-output name=x::y";
+      expect(neutralizeWorkflowCommands(input)).toBe(expected);
+    });
+
+    it("should handle empty string", () => {
+      expect(neutralizeWorkflowCommands("")).toBe("");
+    });
+
+    it("should handle string with only ::", () => {
+      expect(neutralizeWorkflowCommands("::")).toBe(": :");
+    });
+
+    it("should handle multiple :: at line start", () => {
+      const input = "::::test";
+      const expected = ": :::test";
+      expect(neutralizeWorkflowCommands(input)).toBe(expected);
+    });
+
+    it("should preserve :: after spaces", () => {
+      const input = "  ::command";
+      expect(neutralizeWorkflowCommands(input)).toBe(input);
+    });
+
+    it("should handle multiline with mixed patterns", () => {
+      const input = "First line\n::error::Bad\nmiddle::text\n::warning::Watch out";
+      const expected = "First line\n: :error::Bad\nmiddle::text\n: :warning::Watch out";
+      expect(neutralizeWorkflowCommands(input)).toBe(expected);
+    });
+
+    it("should handle non-string input gracefully", () => {
+      // @ts-expect-error - Testing non-string input
+      expect(neutralizeWorkflowCommands(null)).toBe(null);
+      // @ts-expect-error - Testing non-string input
+      expect(neutralizeWorkflowCommands(undefined)).toBe(undefined);
+      // @ts-expect-error - Testing non-string input
+      expect(neutralizeWorkflowCommands(123)).toBe(123);
+    });
+
+    it("should neutralize real workflow command examples", () => {
+      const commands = [
+        { input: "::add-mask::secret", expected: ": :add-mask::secret" },
+        { input: "::stop-commands::token", expected: ": :stop-commands::token" },
+        { input: "::group::My Group", expected: ": :group::My Group" },
+        { input: "::endgroup::", expected: ": :endgroup::" },
+        { input: "::save-state name=foo::bar", expected: ": :save-state name=foo::bar" },
+      ];
+
+      for (const { input, expected } of commands) {
+        expect(neutralizeWorkflowCommands(input)).toBe(expected);
+      }
+    });
+
+    it("should handle file content with potential workflow commands", () => {
+      const fileContent = `
+Some text here
+::error::This is in the file
+More content
+::set-output name=test::value
+End of file`;
+      const expected = `
+Some text here
+: :error::This is in the file
+More content
+: :set-output name=test::value
+End of file`;
+      expect(neutralizeWorkflowCommands(fileContent)).toBe(expected);
+    });
+  });
+
+  describe("safeInfo", () => {
+    it("should call core.info with neutralized message", () => {
+      const message = "::error::test";
+      safeInfo(message);
+      expect(core.info).toHaveBeenCalledWith(": :error::test");
+    });
+
+    it("should handle safe messages without modification", () => {
+      const message = "This is a safe message";
+      safeInfo(message);
+      expect(core.info).toHaveBeenCalledWith(message);
+    });
+
+    it("should neutralize multiline messages", () => {
+      const message = "Line 1\n::error::Line 2";
+      safeInfo(message);
+      expect(core.info).toHaveBeenCalledWith("Line 1\n: :error::Line 2");
+    });
+  });
+
+  describe("safeDebug", () => {
+    it("should call core.debug with neutralized message", () => {
+      const message = "::debug::test";
+      safeDebug(message);
+      expect(core.debug).toHaveBeenCalledWith(": :debug::test");
+    });
+
+    it("should handle safe messages without modification", () => {
+      const message = "Debug info";
+      safeDebug(message);
+      expect(core.debug).toHaveBeenCalledWith(message);
+    });
+  });
+
+  describe("safeWarning", () => {
+    it("should call core.warning with neutralized message", () => {
+      const message = "::warning::test";
+      safeWarning(message);
+      expect(core.warning).toHaveBeenCalledWith(": :warning::test");
+    });
+
+    it("should handle safe messages without modification", () => {
+      const message = "Warning message";
+      safeWarning(message);
+      expect(core.warning).toHaveBeenCalledWith(message);
+    });
+  });
+
+  describe("safeError", () => {
+    it("should call core.error with neutralized message", () => {
+      const message = "::error::test";
+      safeError(message);
+      expect(core.error).toHaveBeenCalledWith(": :error::test");
+    });
+
+    it("should handle safe messages without modification", () => {
+      const message = "Error message";
+      safeError(message);
+      expect(core.error).toHaveBeenCalledWith(message);
+    });
+  });
+
+  describe("integration tests", () => {
+    it("should prevent workflow command injection from user input", () => {
+      // Simulate user input that tries to inject workflow commands
+      const userInput = "User message\n::set-output name=admin::true";
+      safeInfo(userInput);
+      expect(core.info).toHaveBeenCalledWith("User message\n: :set-output name=admin::true");
+    });
+
+    it("should handle command names from comment body", () => {
+      const commandName = "::stop-commands::token";
+      safeInfo(`Command: ${commandName}`);
+      expect(core.info).toHaveBeenCalledWith("Command: ::stop-commands::token");
+    });
+
+    it("should protect file content logging", () => {
+      const fileLines = ["::add-mask::password123", "normal line", "::error::fake error"];
+      fileLines.forEach(line => safeInfo(line));
+
+      expect(core.info).toHaveBeenNthCalledWith(1, ": :add-mask::password123");
+      expect(core.info).toHaveBeenNthCalledWith(2, "normal line");
+      expect(core.info).toHaveBeenNthCalledWith(3, ": :error::fake error");
+    });
+  });
+});