diff --git a/ext/fileinfo/fileinfo.c b/ext/fileinfo/fileinfo.c
index d3680c5755f2..c0cc8877bf99 100644
--- a/ext/fileinfo/fileinfo.c
+++ b/ext/fileinfo/fileinfo.c
@@ -344,6 +344,9 @@ PHP_FUNCTION(finfo_file)
 		RETURN_THROWS();
 	}
 	php_stream_context *context = php_stream_context_from_zval(zcontext, false);
+	if (!context) {
+		RETURN_THROWS();
+	}
 
 	/* Set options for the current file/buffer. */
 	if (options) {
diff --git a/ext/fileinfo/tests/gh18267.phpt b/ext/fileinfo/tests/gh18267.phpt
new file mode 100644
index 000000000000..ba7647288d1d
--- /dev/null
+++ b/ext/fileinfo/tests/gh18267.phpt
@@ -0,0 +1,14 @@
+--TEST--
+GH-18267 finfo_file() assertion trigger on NULL stream context
+--EXTENSIONS--
+fileinfo
+--FILE--
+<?php
+$cls = new finfo();
+try {
+    $cls->file("test",FILEINFO_NONE, STDERR);
+} catch (\TypeError $e) {
+    echo $e->getMessage(); 
+}
+--EXPECT--
+finfo::file(): supplied resource is not a valid Stream-Context resource