diff --git a/src/system/kernel/heap.cpp b/src/system/kernel/heap.cpp
index c2e611605e..e4e2dd5e41 100644
--- a/src/system/kernel/heap.cpp
+++ b/src/system/kernel/heap.cpp
@@ -2263,6 +2263,7 @@ realloc(void *address, size_t newSize)
 				// there is enough room available for the newSize
 				TRACE(("realloc(): new size %ld fits in old area %ld with %ld "
 					"available\n", newSize, area, available));
+				info->allocation_size = newSize;
 				return address;
 			}
 
diff --git a/src/system/libroot/posix/malloc_debug/heap.cpp b/src/system/libroot/posix/malloc_debug/heap.cpp
index ad8f88faac..c25a807156 100644
--- a/src/system/libroot/posix/malloc_debug/heap.cpp
+++ b/src/system/libroot/posix/malloc_debug/heap.cpp
@@ -1689,6 +1689,7 @@ realloc(void *address, size_t newSize)
 				// there is enough room available for the newSize
 				INFO(("realloc(): new size %ld fits in old area %ld with %ld "
 					"available\n", newSize, area, available));
+				info->allocation_size = newSize;
 				return address;
 			}