Commit 9eb8831b73 for ffmpeg

commit 9eb8831b73872e48fa8a5695be75e584032318d0
Author: Michael Niedermayer <michael@niedermayer.cc>
Date:   Tue Oct 6 23:22:54 2026 +0200

    doc/protocols: State that the shared cache directories must be trusted

    Documenting that the directories must not be writable by untrusted users
    was suggested in the report.

    Documentation for umsIH5gcyBXl (AISLE-2026-0111-00168)
    Found-by: Joshua Rogers <joshua.rogers@aisle.com>

diff --git a/doc/protocols.texi b/doc/protocols.texi
index 287d972f68..db1433f733 100644
--- a/doc/protocols.texi
+++ b/doc/protocols.texi
@@ -1790,6 +1790,9 @@ The accepted options are:

 @item cache_dir
 Path to the directory where cache files are stored. This option is required.
+Anyone who can write to this directory or to @option{metadata_dir} can alter
+the data read by all users of the cache, or make them crash, so neither may be
+writable by untrusted users.

 @item metadata_dir
 Path to the directory where metadata files are stored. Optional. If not