diff --git a/Userland/Libraries/LibGL/Buffer.cpp b/Userland/Libraries/LibGL/Buffer.cpp
index 4b8ceacb1f3..e44bff386cc 100644
--- a/Userland/Libraries/LibGL/Buffer.cpp
+++ b/Userland/Libraries/LibGL/Buffer.cpp
@@ -61,7 +61,7 @@ void GLContext::gl_buffer_sub_data(GLenum target, GLintptr offset, GLsizeiptr si
 
     auto& target_buffer = target == GL_ELEMENT_ARRAY_BUFFER ? m_element_array_buffer : m_array_buffer;
     RETURN_WITH_ERROR_IF(!target_buffer, GL_INVALID_OPERATION);
-    RETURN_WITH_ERROR_IF((offset + size) > target_buffer->size(), GL_INVALID_VALUE);
+    RETURN_WITH_ERROR_IF(static_cast<size_t>(offset + size) > target_buffer->size(), GL_INVALID_VALUE);
 
     target_buffer->replace_data(data, offset, size);
 }
diff --git a/Userland/Libraries/LibGL/GL/glplatform.h b/Userland/Libraries/LibGL/GL/glplatform.h
index e57f6edd4c6..824a3671053 100644
--- a/Userland/Libraries/LibGL/GL/glplatform.h
+++ b/Userland/Libraries/LibGL/GL/glplatform.h
@@ -32,7 +32,7 @@ typedef long GLintptr;
 typedef unsigned int GLuint;
 typedef int GLfixed;
 typedef int GLsizei;
-typedef unsigned long GLsizeiptr;
+typedef long GLsizeiptr;
 typedef void GLvoid;
 typedef float GLfloat;
 typedef double GLclampd;