diff --git a/binaries/data/mods/public/simulation/ai/petra/config.js b/binaries/data/mods/public/simulation/ai/petra/config.js
index d816ebf464..20c9a35e67 100644
--- a/binaries/data/mods/public/simulation/ai/petra/config.js
+++ b/binaries/data/mods/public/simulation/ai/petra/config.js
@@ -346,7 +346,7 @@ PETRA.Config.prototype.Serialize = function()
 {
 	var data = {};
 	for (const key in this)
-		if (this.hasOwnProperty(key) && key != "debug")
+		if (Object.hasOwn(this, key) && key != "debug")
 			data[key] = this[key];
 	return data;
 };
diff --git a/binaries/data/mods/public/simulation/components/AIInterface.js b/binaries/data/mods/public/simulation/components/AIInterface.js
index 88ae8d89d1..cb4e7b7542 100644
--- a/binaries/data/mods/public/simulation/components/AIInterface.js
+++ b/binaries/data/mods/public/simulation/components/AIInterface.js
@@ -48,7 +48,7 @@ AIInterface.prototype.Serialize = function()
 	const state = {};
 	for (var key in this)
 	{
-		if (!this.hasOwnProperty(key))
+		if (!Object.hasOwn(this, key))
 			continue;
 		if (typeof this[key] == "function")
 			continue;
@@ -63,7 +63,7 @@ AIInterface.prototype.Deserialize = function(data)
 {
 	for (const key in data)
 	{
-		if (!data.hasOwnProperty(key))
+		if (!Object.hasOwn(data, key))
 			continue;
 		this[key] = data[key];
 	}
diff --git a/binaries/data/mods/public/simulation/components/Diplomacy.js b/binaries/data/mods/public/simulation/components/Diplomacy.js
index 1bbfb0d385..6890da7c81 100644
--- a/binaries/data/mods/public/simulation/components/Diplomacy.js
+++ b/binaries/data/mods/public/simulation/components/Diplomacy.js
@@ -19,7 +19,7 @@ Diplomacy.prototype.Serialize = function()
 {
 	const state = {};
 	for (const key of this.SerializableAttributes)
-		if (this.hasOwnProperty(key))
+		if (Object.hasOwn(this, key))
 			state[key] = this[key];
 
 	return state;
diff --git a/binaries/data/mods/public/simulation/components/Player.js b/binaries/data/mods/public/simulation/components/Player.js
index aa4f24ef37..6f73db254d 100644
--- a/binaries/data/mods/public/simulation/components/Player.js
+++ b/binaries/data/mods/public/simulation/components/Player.js
@@ -30,7 +30,7 @@ Player.prototype.Serialize = function()
 {
 	const state = {};
 	for (const key in this)
-		if (this.hasOwnProperty(key))
+		if (Object.hasOwn(this, key))
 			state[key] = this[key];
 
 	// Modified by GUI, so don't serialise.
diff --git a/binaries/data/mods/public/simulation/components/ProductionQueue.js b/binaries/data/mods/public/simulation/components/ProductionQueue.js
index d31ee2eb04..7800d59cf2 100644
--- a/binaries/data/mods/public/simulation/components/ProductionQueue.js
+++ b/binaries/data/mods/public/simulation/components/ProductionQueue.js
@@ -202,7 +202,7 @@ ProductionQueue.prototype.Item.prototype.Serialize = function()
 {
 	const result = {};
 	for (const att of this.SerializableAttributes)
-		if (this.hasOwnProperty(att))
+		if (Object.hasOwn(this, att))
 			result[att] = this[att];
 	return result;
 };
@@ -236,7 +236,7 @@ ProductionQueue.prototype.Serialize = function()
 		result.queue.push(item.Serialize());
 
 	for (const att of this.SerializableAttributes)
-		if (this.hasOwnProperty(att))
+		if (Object.hasOwn(this, att))
 			result[att] = this[att];
 
 	return result;
diff --git a/binaries/data/mods/public/simulation/components/Researcher.js b/binaries/data/mods/public/simulation/components/Researcher.js
index 0425ae7bdd..1ab5bef73d 100644
--- a/binaries/data/mods/public/simulation/components/Researcher.js
+++ b/binaries/data/mods/public/simulation/components/Researcher.js
@@ -129,7 +129,7 @@ Researcher.prototype.Item.prototype.Serialize = function(id)
 		"id": id
 	};
 	for (const att of this.SerializableAttributes)
-		if (this.hasOwnProperty(att))
+		if (Object.hasOwn(this, att))
 			result[att] = this[att];
 	return result;
 };
diff --git a/binaries/data/mods/public/simulation/components/TechnologyManager.js b/binaries/data/mods/public/simulation/components/TechnologyManager.js
index 131b334c75..cf06f0d181 100644
--- a/binaries/data/mods/public/simulation/components/TechnologyManager.js
+++ b/binaries/data/mods/public/simulation/components/TechnologyManager.js
@@ -183,7 +183,7 @@ TechnologyManager.prototype.Technology.prototype.Serialize = function()
 {
 	const result = {};
 	for (const att of this.SerializableAttributes)
-		if (this.hasOwnProperty(att))
+		if (Object.hasOwn(this, att))
 			result[att] = this[att];
 	return result;
 };
@@ -227,7 +227,7 @@ TechnologyManager.prototype.Serialize = function()
 {
 	const result = {};
 	for (const att of this.SerializableAttributes)
-		if (this.hasOwnProperty(att))
+		if (Object.hasOwn(this, att))
 			result[att] = this[att];
 
 	result.researchQueued = [];
diff --git a/binaries/data/mods/public/simulation/components/Trainer.js b/binaries/data/mods/public/simulation/components/Trainer.js
index 8588f93f9c..8bbaabdd66 100644
--- a/binaries/data/mods/public/simulation/components/Trainer.js
+++ b/binaries/data/mods/public/simulation/components/Trainer.js
@@ -406,7 +406,7 @@ Trainer.prototype.Item.prototype.Serialize = function(id)
 		"id": id
 	};
 	for (const att of this.SerializableAttributes)
-		if (this.hasOwnProperty(att))
+		if (Object.hasOwn(this, att))
 			result[att] = this[att];
 	return result;
 };
@@ -441,7 +441,7 @@ Trainer.prototype.Serialize = function()
 		"queue": queue
 	};
 	for (const att of this.SerializableAttributes)
-		if (this.hasOwnProperty(att))
+		if (Object.hasOwn(this, att))
 			result[att] = this[att];
 
 	return result;
diff --git a/binaries/data/mods/public/simulation/components/tests/setup.js b/binaries/data/mods/public/simulation/components/tests/setup.js
index 0209f27b71..72b94cc085 100644
--- a/binaries/data/mods/public/simulation/components/tests/setup.js
+++ b/binaries/data/mods/public/simulation/components/tests/setup.js
@@ -151,7 +151,7 @@ global.SerializationCycle = function(cmp)
 	{
 		data = {};
 		for (const att of cmp)
-			if (cmp.hasOwnProperty(att))
+			if (Object.hasOwn(cmp, att))
 				data[att] = cmp[att];
 	}
 
diff --git a/eslint.config.mjs b/eslint.config.mjs
index 1511c802c2..b50877c430 100644
--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@@ -61,6 +61,7 @@ const configEslintRecommended = {
 		"no-nonoctal-decimal-escape": "warn",
 		"no-obj-calls": "warn",
 		"no-octal": "warn",
+		"no-prototype-builtins": "warn",
 		"no-redeclare": "warn",
 		"no-regex-spaces": "warn",
 		"no-self-assign": "warn",