diff --git a/.github/workflows/e2e-tests.yml b/.github/workflows/e2e-tests.yml
index be9b72ff74d..89f764c0da6 100644
--- a/.github/workflows/e2e-tests.yml
+++ b/.github/workflows/e2e-tests.yml
@@ -128,6 +128,10 @@ jobs:
               cd e2e/bug-14514
               composer install
               ../../bin/phpstan analyze bug-14515.php
+          - script: |
+              cd e2e/bug-14724
+              composer install
+              ../../bin/phpstan analyze app/
           - script: |
               cd e2e/bug10449
               ../../bin/phpstan analyze
diff --git a/e2e/bug-14724/.gitignore b/e2e/bug-14724/.gitignore
new file mode 100644
index 00000000000..61ead86667c
--- /dev/null
+++ b/e2e/bug-14724/.gitignore
@@ -0,0 +1 @@
+/vendor
diff --git a/e2e/bug-14724/README b/e2e/bug-14724/README
new file mode 100644
index 00000000000..68670114dc5
--- /dev/null
+++ b/e2e/bug-14724/README
@@ -0,0 +1 @@
+this test case intentionally ships with a invalid composer.json (according to schema), as this is what made PHPStan crash at startup.
diff --git a/e2e/bug-14724/app/classes/path-1/A.php b/e2e/bug-14724/app/classes/path-1/A.php
new file mode 100644
index 00000000000..7643c3311a9
--- /dev/null
+++ b/e2e/bug-14724/app/classes/path-1/A.php
@@ -0,0 +1,3 @@
+<?php
+
+class A {}
diff --git a/e2e/bug-14724/app/classes/path-2/B.php b/e2e/bug-14724/app/classes/path-2/B.php
new file mode 100644
index 00000000000..24196845ad3
--- /dev/null
+++ b/e2e/bug-14724/app/classes/path-2/B.php
@@ -0,0 +1,5 @@
+<?php
+
+class B {
+	public function doA(A $a) {}
+}
diff --git a/e2e/bug-14724/app/file.php b/e2e/bug-14724/app/file.php
new file mode 100644
index 00000000000..6bb18cfc7cb
--- /dev/null
+++ b/e2e/bug-14724/app/file.php
@@ -0,0 +1,3 @@
+<?php
+
+// intentional empty file
diff --git a/e2e/bug-14724/composer.json b/e2e/bug-14724/composer.json
new file mode 100644
index 00000000000..694b2cc74ca
--- /dev/null
+++ b/e2e/bug-14724/composer.json
@@ -0,0 +1,15 @@
+{
+	"autoload-dev": {
+		"classmap": [
+			[
+				"app/classes/path-1",
+				"app/classes/path-2"
+			]
+		],
+		"files": [
+			[
+				"app/file.php"
+			]
+		]
+	}
+}
diff --git a/e2e/bug-14724/composer.lock b/e2e/bug-14724/composer.lock
new file mode 100644
index 00000000000..ba8d41762cc
--- /dev/null
+++ b/e2e/bug-14724/composer.lock
@@ -0,0 +1,18 @@
+{
+    "_readme": [
+        "This file locks the dependencies of your project to a known state",
+        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
+        "This file is @generated automatically"
+    ],
+    "content-hash": "d751713988987e9331980363e24189ce",
+    "packages": [],
+    "packages-dev": [],
+    "aliases": [],
+    "minimum-stability": "stable",
+    "stability-flags": {},
+    "prefer-stable": false,
+    "prefer-lowest": false,
+    "platform": {},
+    "platform-dev": {},
+    "plugin-api-version": "2.9.0"
+}
diff --git a/src/Reflection/BetterReflection/SourceLocator/ComposerJsonAndInstalledJsonSourceLocatorMaker.php b/src/Reflection/BetterReflection/SourceLocator/ComposerJsonAndInstalledJsonSourceLocatorMaker.php
index 83e7d869928..58637b2b11f 100644
--- a/src/Reflection/BetterReflection/SourceLocator/ComposerJsonAndInstalledJsonSourceLocatorMaker.php
+++ b/src/Reflection/BetterReflection/SourceLocator/ComposerJsonAndInstalledJsonSourceLocatorMaker.php
@@ -21,8 +21,10 @@
 use function count;
 use function dirname;
 use function glob;
+use function is_array;
 use function is_dir;
 use function is_file;
+use function is_string;
 use function str_contains;
 use const GLOB_ONLYDIR;
 
@@ -175,7 +177,19 @@ public function create(string $projectInstallationPath): ?SourceLocator
 	 */
 	private function packageToPsr4AutoloadNamespaces(array $package, string $autoloadSection = 'autoload'): array
 	{
-		return array_map(static fn ($namespacePaths): array => (array) $namespacePaths, $package[$autoloadSection]['psr-4'] ?? []);
+		$psr4 = $package[$autoloadSection]['psr-4'] ?? [];
+		if (!is_array($psr4)) {
+			return []; // skip on invalid data
+		}
+		foreach ($psr4 as $key => $namespacePaths) {
+			$stringArray = $this->toStringArray($namespacePaths);
+			if (!is_string($key) || $stringArray === null) {
+				return []; // skip on invalid data
+			}
+
+			$psr4[$key] = $stringArray;
+		}
+		return $psr4;
 	}
 
 	/**
@@ -185,7 +199,19 @@ private function packageToPsr4AutoloadNamespaces(array $package, string $autoloa
 	 */
 	private function packageToPsr0AutoloadNamespaces(array $package, string $autoloadSection = 'autoload'): array
 	{
-		return array_map(static fn ($namespacePaths): array => (array) $namespacePaths, $package[$autoloadSection]['psr-0'] ?? []);
+		$psr0 = $package[$autoloadSection]['psr-0'] ?? [];
+		if (!is_array($psr0)) {
+			return []; // skip on invalid data
+		}
+		foreach ($psr0 as $key => $namespacePaths) {
+			$stringArray = $this->toStringArray($namespacePaths);
+			if (!is_string($key) || $stringArray === null) {
+				return []; // skip on invalid data
+			}
+
+			$psr0[$key] = $stringArray;
+		}
+		return $psr0;
 	}
 
 	/**
@@ -195,7 +221,7 @@ private function packageToPsr0AutoloadNamespaces(array $package, string $autoloa
 	 */
 	private function packageToClassMapPaths(array $package, string $autoloadSection = 'autoload'): array
 	{
-		return $package[$autoloadSection]['classmap'] ?? [];
+		return $this->toStringArray($package[$autoloadSection]['classmap'] ?? []) ?? [];
 	}
 
 	/**
@@ -205,7 +231,7 @@ private function packageToClassMapPaths(array $package, string $autoloadSection
 	 */
 	private function packageToFilePaths(array $package, string $autoloadSection = 'autoload'): array
 	{
-		return $package[$autoloadSection]['files'] ?? [];
+		return $this->toStringArray($package[$autoloadSection]['files'] ?? []) ?? [];
 	}
 
 	/**
@@ -257,4 +283,22 @@ private function prefixPaths(array $paths, string $prefix): array
 		return array_map(static fn (string $path): string => $prefix . $path, $paths);
 	}
 
+	/**
+	 * @param array<mixed>|string $stringOrArray
+	 * @return array<string>|null
+	 */
+	private function toStringArray(array|string $stringOrArray): ?array
+	{
+		if (is_string($stringOrArray)) {
+			return (array) $stringOrArray;
+		}
+
+		foreach ($stringOrArray as $stringOrArrayItem) {
+			if (!is_string($stringOrArrayItem)) {
+				return null;
+			}
+		}
+		return $stringOrArray;
+	}
+
 }