diff --git a/completions/aptitude b/completions/aptitude
index 8b41f29a2a1..0e7a0143638 100644
--- a/completions/aptitude
+++ b/completions/aptitude
@@ -54,7 +54,7 @@ _comp_cmd_aptitude()
         --target-release | --default-release | -${noargopts}t)
             COMPREPLY=($(apt-cache policy |
                 command grep "release.o=Debian,a=$cur" |
-                command sed -e "s/.*a=\(\w*\).*/\1/" | uniq 2>/dev/null))
+                command sed -e "s/.*a=\([_[:alnum:]]*\).*/\1/" | uniq 2>/dev/null))
             return
             ;;
     esac