Steve Kemp discovered that osh, a shell intended to restrict the actions of the user, contains two buffer overflows, in processing environment variables and file redirections. These vulnerabilities could be used to execute arbitrary code, overriding any restrictions placed on the shell.
For the stable distribution (woody) this problem has been fixed in version 1.7-11woody1.
The old stable distribution (potato) is affected by this problem, and may be fixed in a future advisory on a time-available basis.
For the unstable distribution (sid) this problem is fixed in version 1.7-12.
We recommend that you update your osh package.