https://github.com/strukturag/libde265/commit/7e4faf254bbd2e52b0f216cb987573a2cce97b54
Straight from upstream
To be removed with libde265-1.0.15 or later

From 7e4faf254bbd2e52b0f216cb987573a2cce97b54 Mon Sep 17 00:00:00 2001
From: Dirk Farin <dirk.farin@gmail.com>
Date: Thu, 23 Nov 2023 19:38:34 +0100
Subject: [PATCH] prevent endless loop for #434 input

---
 libde265/slice.cc | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libde265/slice.cc b/libde265/slice.cc
index 435123dc..3a8a8de1 100644
--- a/libde265/slice.cc
+++ b/libde265/slice.cc
@@ -2582,6 +2582,11 @@ static int decode_rqt_root_cbf(thread_context* tctx)
 
 static int decode_ref_idx_lX(thread_context* tctx, int numRefIdxLXActive)
 {
+  // prevent endless loop when 'numRefIdxLXActive' is invalid
+  if (numRefIdxLXActive <= 1) {
+    return 0;
+  }
+
   logtrace(LogSlice,"# ref_idx_lX\n");
 
   int cMax = numRefIdxLXActive-1;