diff --git a/lib/matplotlib/mpl-data/stylelib/classic.mplstyle b/lib/matplotlib/mpl-data/stylelib/classic.mplstyle
index cd636d65c7c8..56a0461f61f3 100644
--- a/lib/matplotlib/mpl-data/stylelib/classic.mplstyle
+++ b/lib/matplotlib/mpl-data/stylelib/classic.mplstyle
@@ -111,21 +111,6 @@ text.usetex         : False  # use latex for all text handling. The following fo
                              # If another font is desired which can loaded using the
                              # LaTeX \usepackage command, please inquire at the
                              # matplotlib mailing list
-text.latex.preamble :  # IMPROPER USE OF THIS FEATURE WILL LEAD TO LATEX FAILURES
-                       # AND IS THEREFORE UNSUPPORTED. PLEASE DO NOT ASK FOR HELP
-                       # IF THIS FEATURE DOES NOT DO WHAT YOU EXPECT IT TO.
-                       # text.latex.preamble is a single line of LaTeX code that
-                       # will be passed on to the LaTeX system. It may contain
-                       # any code that is valid for the LaTeX "preamble", i.e.
-                       # between the "\documentclass" and "\begin{document}"
-                       # statements.
-                       # Note that it has to be put on a single line, which may
-                       # become quite long.
-                       # The following packages are always loaded with usetex, so
-                       # beware of package collisions:
-                       #   color, fix-cm, geometry, graphicx, textcomp.
-                       # Adobe Postscript (PSSNFS) font packages may also be
-                       # loaded, depending on your font settings.
 
 text.hinting : auto   # May be one of the following:
                       #   'none': Perform no hinting
@@ -452,7 +437,6 @@ pdf.use14corefonts : False
 # pgf backend params
 pgf.texsystem       : xelatex
 pgf.rcfonts         : True
-pgf.preamble        :
 
 # svg backend params
 svg.image_inline : True       # write raster image data directly into the svg file
diff --git a/lib/matplotlib/style/__init__.py b/lib/matplotlib/style/__init__.py
index 80c6de00a18d..0f1bcade07bc 100644
--- a/lib/matplotlib/style/__init__.py
+++ b/lib/matplotlib/style/__init__.py
@@ -37,7 +37,10 @@
     'webagg.port_retries', 'webagg.open_in_browser', 'backend_fallback',
     'toolbar', 'timezone', 'figure.max_open_warning',
     'figure.raise_window', 'savefig.directory', 'tk.window_focus',
-    'docstring.hardcopy', 'date.epoch'}
+    'docstring.hardcopy', 'date.epoch',
+    # Preamble params allow arbitrary LaTeX command injection.
+    'text.latex.preamble', 'pgf.preamble',
+}
 
 
 @_docstring.Substitution(