diff --git a/logstash-core/build.gradle b/logstash-core/build.gradle
index 30c64040c33..2b3bb6e6688 100644
--- a/logstash-core/build.gradle
+++ b/logstash-core/build.gradle
@@ -124,6 +124,8 @@ tasks.register("javaTests", Test) {
     exclude '/org/logstash/plugins/factory/PluginFactoryExtTest.class'
     exclude '/org/logstash/execution/ObservedExecutionTest.class'
 
+    maxHeapSize = "12g"
+
     jacoco {
         enabled = true
         destinationFile = layout.buildDirectory.file('jacoco/test.exec').get().asFile
diff --git a/logstash-core/src/main/java/org/logstash/common/BufferedTokenizerExt.java b/logstash-core/src/main/java/org/logstash/common/BufferedTokenizerExt.java
index e2c476520c1..2161dc90049 100644
--- a/logstash-core/src/main/java/org/logstash/common/BufferedTokenizerExt.java
+++ b/logstash-core/src/main/java/org/logstash/common/BufferedTokenizerExt.java
@@ -48,7 +48,7 @@ public class BufferedTokenizerExt extends RubyObject {
     private RubyString delimiter = NEW_LINE;
     private int sizeLimit;
     private boolean hasSizeLimit;
-    private int inputSize;
+    private long inputSize;
     private boolean bufferFullErrorNotified = false;
     private String encodingName;
 
diff --git a/logstash-core/src/test/java/org/logstash/common/BufferedTokenizerExtWithSizeLimitTest.java b/logstash-core/src/test/java/org/logstash/common/BufferedTokenizerExtWithSizeLimitTest.java
index 9a07242369d..16181bb6f18 100644
--- a/logstash-core/src/test/java/org/logstash/common/BufferedTokenizerExtWithSizeLimitTest.java
+++ b/logstash-core/src/test/java/org/logstash/common/BufferedTokenizerExtWithSizeLimitTest.java
@@ -38,14 +38,19 @@
 @SuppressWarnings("unchecked")
 public final class BufferedTokenizerExtWithSizeLimitTest extends RubyTestBase {
 
+    public static final int GB = 1024 * 1024 * 1024;
     private BufferedTokenizerExt sut;
     private ThreadContext context;
 
     @Before
     public void setUp() {
+        initSUTWithSizeLimit(10);
+    }
+
+    private void initSUTWithSizeLimit(int sizeLimit) {
         sut = new BufferedTokenizerExt(RubyUtil.RUBY, RubyUtil.BUFFERED_TOKENIZER);
         context = RUBY.getCurrentContext();
-        IRubyObject[] args = {RubyUtil.RUBY.newString("\n"), RubyUtil.RUBY.newFixnum(10)};
+        IRubyObject[] args = {RubyUtil.RUBY.newString("\n"), RubyUtil.RUBY.newFixnum(sizeLimit)};
         sut.init(context, args);
     }
 
@@ -108,4 +113,29 @@ public void giveMultipleSegmentsThatGeneratesMultipleBufferFullErrorsThenIsAbleT
         RubyArray<RubyString> tokens = (RubyArray<RubyString>) sut.extract(context, RubyUtil.RUBY.newString("ccc\nddd\n"));
         assertEquals(List.of("ccccc", "ddd"), tokens);
     }
+
+    @Test
+    public void givenMaliciousInputExtractDoesntOverflow() {
+        assertEquals("Xmx must equals to what's defined in the Gradle's javaTests task",
+                12L * GB, Runtime.getRuntime().maxMemory());
+
+        // re-init the tokenizer with big sizeLimit
+        initSUTWithSizeLimit((int) (2L * GB) - 3);
+        // Integer.MAX_VALUE is 2 * GB
+        String bigFirstPiece = generateString("a", Integer.MAX_VALUE - 1024);
+        sut.extract(context, RubyUtil.RUBY.newString(bigFirstPiece));
+
+        // add another small fragment to trigger int overflow
+        // sizeLimit is (2^32-1)-3 first segment length is (2^32-1) - 1024 second is 1024 +2
+        // so the combined length of first and second is > sizeLimit and should throw an expection
+        // but because of overflow it's negative and happens to be < sizeLimit
+        Exception thrownException = assertThrows(IllegalStateException.class, () -> {
+            sut.extract(context, RubyUtil.RUBY.newString(generateString("a", 1024 + 2)));
+        });
+        assertThat(thrownException.getMessage(), containsString("input buffer full"));
+    }
+
+    private String generateString(String fill, int size) {
+        return fill.repeat(size);
+    }
 }
\ No newline at end of file