уже есть патчи до сабжа
пофиксено:
Bash has problems parsing certain constructs inside Posix-style $(...)
command substitutions, mostly with backslash-quoting and reserved word
recognition. This is an issue because the contents are parsed at the
time the word containing the command substitution is read.
A line inadvertenly omitted from a submitted patch results in core dumps
when attempting filename completion while using the bash-completion
package.
Under certain circumstances, constructs containing command substitutions
prevent PS1 from being re-evaluated and updated before being displayed.
In some cases, enabling the `checkjobs' shell option will cause the shell
to core dump when executing the `exit' builtin.
The `declare' builtin dumped core when attempting to assign associative
array indices containing some special characters, even when they were
quoted before being expanded.
Bash did not parse pipelines using the |& construct correctly if the
pipeline elements were not simple commands.
Bash had a number of problems parsing associative array subscripts containing
special characters. The subscripts are supposed to be read as if they are
enclosed between double quotes.
When the read builtin returned due to a timeout supplied with the -t option,
it did not restore any modified terminal attribtues.
Bash has problems parsing comments in case statements when they appear in
$(...) subshells.
bash-4.0 regression with here documents and multiline subshells
патчи здесь: ftp://ftp.gnu.org/gnu/bash/bash-4.0-patches