1 files changed, 1 insertions, 1 deletions
diff --git a/strmatch/apr_strmatch.c b/strmatch/apr_strmatch.c
index 75ed6153c..6a4bf6f9e 100644
--- a/strmatch/apr_strmatch.c
+++ b/strmatch/apr_strmatch.c
@@ -74,7 +74,7 @@ static const char *match_boyer_moore_horspool_nocase(
             }
             s_tmp--;
         }
-        s_next += shift[apr_tolower(*s_next)];
+        s_next += shift[(unsigned char)apr_tolower(*s_next)];
     }
     return NULL;
 }