diff --git a/debian/patches/0082-fix-ass-incorrect-null-copy.patch b/debian/patches/0082-fix-ass-incorrect-null-copy.patch
new file mode 100644
index 000000000..8268f816a
--- /dev/null
+++ b/debian/patches/0082-fix-ass-incorrect-null-copy.patch
@@ -0,0 +1,14 @@
+Index: FFmpeg/libavformat/assenc.c
+===================================================================
+--- FFmpeg.orig/libavformat/assenc.c
++++ FFmpeg/libavformat/assenc.c
+@@ -67,7 +67,8 @@ static int write_header(AVFormatContext
+                 ass->trailer = trailer;
+         }
+ 
+-        ffio_write_lines(s->pb, par->extradata, header_size, NULL);
++        header_size = av_strnlen(par->extradata, header_size);
++        ffio_write_lines(s->pb, par->extradata, (int)header_size, NULL);
+ 
+         ass->ssa_mode = !strstr(par->extradata, "\n[V4+ Styles]");
+         if (!strstr(par->extradata, "\n[Events]"))
diff --git a/debian/patches/series b/debian/patches/series
index 4afca3726..e4e9f3883 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -79,4 +79,5 @@
 0079-videotoolbox-remove-opengl-compatability.patch
 0080-use-dynamic-pool-for-vpl-qsv-hwupload.patch
 0081-backport-av1-videotoolbox.patch
+0082-fix-ass-incorrect-null-copy.patch
 0083-default-to-input-timebase-for-streamcopy.patch