diff --git a/src/Magnum/Test/CubeMapTextureGLTest.cpp b/src/Magnum/Test/CubeMapTextureGLTest.cpp
index 0827c80c8..1e9fbb0e6 100644
--- a/src/Magnum/Test/CubeMapTextureGLTest.cpp
+++ b/src/Magnum/Test/CubeMapTextureGLTest.cpp
@@ -195,6 +195,7 @@ CubeMapTextureGLTest::CubeMapTextureGLTest() {
         _compressedDataStorage = {};
         #endif
         _compressedDataOffset = 0;
+        _compressedFullDataOffset = 0;
     }
 }