diff --git a/packages/workflow/src/errors/abstract/execution-base.error.ts b/packages/workflow/src/errors/abstract/execution-base.error.ts
index 74b9b8a0360..56a80ff746f 100644
--- a/packages/workflow/src/errors/abstract/execution-base.error.ts
+++ b/packages/workflow/src/errors/abstract/execution-base.error.ts
@@ -27,7 +27,13 @@ export abstract class ExecutionBaseError extends BaseError {
 	constructor(message: string, options: ExecutionBaseErrorOptions = {}) {
 		super(message, options);
 
-		this.name = this.constructor.name;
+		// Defined, not assigned: assignment throws when `Error.prototype` is frozen (task runner secure mode)
+		Object.defineProperty(this, 'name', {
+			value: this.constructor.name,
+			writable: true,
+			enumerable: true,
+			configurable: true,
+		});
 		this.timestamp = Date.now();
 
 		const { cause, errorResponse } = options;
diff --git a/packages/workflow/src/errors/workflow-activation.error.ts b/packages/workflow/src/errors/workflow-activation.error.ts
index 1c524aad9eb..f6345be949e 100644
--- a/packages/workflow/src/errors/workflow-activation.error.ts
+++ b/packages/workflow/src/errors/workflow-activation.error.ts
@@ -24,8 +24,17 @@ export class WorkflowActivationError extends ExecutionBaseError {
 		let error = cause as Error;
 		if (cause instanceof ExecutionBaseError) {
 			error = new Error(cause.message);
-			error.constructor = cause.constructor;
-			error.name = cause.name;
+			// Defined, not assigned: a fresh `Error` has no own `constructor`/`name`, so
+			// assignment throws when `Error.prototype` is frozen (task runner secure mode)
+			Object.defineProperties(error, {
+				constructor: {
+					value: cause.constructor,
+					writable: true,
+					enumerable: true,
+					configurable: true,
+				},
+				name: { value: cause.name, writable: true, enumerable: true, configurable: true },
+			});
 			error.stack = cause.stack;
 		}
 		super(message, { cause: error });
diff --git a/packages/workflow/test/errors/execution-base.error.test.ts b/packages/workflow/test/errors/execution-base.error.test.ts
new file mode 100644
index 00000000000..04c8b61019f
--- /dev/null
+++ b/packages/workflow/test/errors/execution-base.error.test.ts
@@ -0,0 +1,28 @@
+import { ExpressionError } from '../../src/errors';
+
+describe('ExecutionBaseError', () => {
+	it('should set name to the concrete class name', () => {
+		const error = new ExpressionError('message');
+
+		expect(error.name).toBe('ExpressionError');
+	});
+
+	describe('with a frozen Error.prototype', () => {
+		const nameDescriptor = Object.getOwnPropertyDescriptor(Error.prototype, 'name')!;
+
+		beforeAll(() => {
+			Object.defineProperty(Error.prototype, 'name', { ...nameDescriptor, writable: false });
+		});
+
+		afterAll(() => {
+			Object.defineProperty(Error.prototype, 'name', nameDescriptor);
+		});
+
+		it('should construct and set name without writing through the prototype', () => {
+			const error = new ExpressionError('Paired item data is unavailable');
+
+			expect(error.name).toBe('ExpressionError');
+			expect(Object.getOwnPropertyDescriptor(error, 'name')?.writable).toBe(true);
+		});
+	});
+});
diff --git a/packages/workflow/test/errors/workflow-activation.error.test.ts b/packages/workflow/test/errors/workflow-activation.error.test.ts
index 7ec518900af..ddb4ea7e7ac 100644
--- a/packages/workflow/test/errors/workflow-activation.error.test.ts
+++ b/packages/workflow/test/errors/workflow-activation.error.test.ts
@@ -1,4 +1,4 @@
-import { WorkflowActivationError } from '../../src/errors';
+import { WorkflowActivationError, WorkflowOperationError } from '../../src/errors';
 
 describe('WorkflowActivationError', () => {
 	it('should default to `error` level', () => {
@@ -44,4 +44,32 @@ describe('WorkflowActivationError', () => {
 
 		expect(error.description).toBe('Actionable detail');
 	});
+
+	describe('with a frozen Error.prototype', () => {
+		const descriptors = {
+			name: Object.getOwnPropertyDescriptor(Error.prototype, 'name')!,
+			constructor: Object.getOwnPropertyDescriptor(Error.prototype, 'constructor')!,
+		};
+
+		beforeAll(() => {
+			for (const [key, descriptor] of Object.entries(descriptors)) {
+				Object.defineProperty(Error.prototype, key, { ...descriptor, writable: false });
+			}
+		});
+
+		afterAll(() => {
+			for (const [key, descriptor] of Object.entries(descriptors)) {
+				Object.defineProperty(Error.prototype, key, descriptor);
+			}
+		});
+
+		it('should wrap an ExecutionBaseError cause without writing through the prototype', () => {
+			const operationCause = new WorkflowOperationError('operation failed');
+
+			const error = new WorkflowActivationError('activation failed', { cause: operationCause });
+
+			expect(error.name).toBe('WorkflowActivationError');
+			expect(error.description).toBe('operation failed');
+		});
+	});
 });