diff --git a/src/mesa/main/bufferobj.c b/src/mesa/main/bufferobj.c
index 30b8b2196ae..bf405b2513f 100644
--- a/src/mesa/main/bufferobj.c
+++ b/src/mesa/main/bufferobj.c
@@ -995,10 +995,11 @@ convert_clear_buffer_data(struct gl_context *ctx,
                           const GLvoid *data, const char *caller)
 {
    GLenum internalformatBase = _mesa_get_format_base_format(internalformat);
+   struct gl_pixelstore_attrib packing = {.Alignment = 1};
 
    if (_mesa_texstore(ctx, 1, internalformatBase, internalformat,
                       0, &clearValue, 1, 1, 1,
-                      format, type, data, &ctx->Unpack)) {
+                      format, type, data, &packing)) {
       return true;
    }
    else {