CVE-2016-9401 Use after free in n/a

Medium 6.2 Published 23 Jan 2017 Updated 6 Aug 2025

Local attackers can bypass restricted shell and trigger use-after-free in Bash, potentially leading to privilege escalation or code execution.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2016-9401?

CVE-2016-9401 is a medium-severity use after free vulnerability in Debian Debian Linux, published on 23 Jan 2017. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

popd in bash might allow local users to bypass the restricted shell and cause a use-after-free via a crafted address.

Weakness: CWE-416

Which versions are affected by CVE-2016-9401?

It affects 8 products.

Linux distribution packages (9)

`bash` SUSE:Linux Enterprise Desktop 12 SP2	All versions	`4.3-82.1`
`bash` SUSE:Linux Enterprise Server 11 SP4	All versions	`3.2-147.35.1`
`bash` SUSE:Linux Enterprise Server 12 SP2	All versions	`4.3-82.1`
`bash` SUSE:Linux Enterprise Server for Raspberry Pi 12 SP2	All versions	`4.3-82.1`
`bash` SUSE:Linux Enterprise Server for SAP Applications 11 SP4	All versions	`3.2-147.35.1`
`bash` SUSE:Linux Enterprise Server for SAP Applications 12 SP2	All versions	`4.3-82.1`
`bash` SUSE:Linux Enterprise Software Development Kit 11 SP4	All versions	`3.2-147.35.1`
`bash` SUSE:Linux Enterprise Software Development Kit 12 SP2	All versions	`4.3-82.1`
`bash` SUSE:Linux Enterprise Workstation Extension 12 SP2	All versions	`4.3-82.1`

Products include Debian Debian Linux, Gnu Bash, Redhat Enterprise Linux Desktop, Redhat Enterprise Linux Server, Redhat Enterprise Linux Server Aus, Redhat Enterprise Linux Server Eus and 2 more.

How do I fix CVE-2016-9401?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2016-9401 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2016-9401 exists.

All Debian Debian Linux vulnerabilities

Sources

Also known as ALPINE-CVE-2016-9401, DEBIAN-CVE-2016-9401, GHSA-888p-vvcc-q364, MGASA-2017-0005, SUSE-SU-2017:1317-1, SUSE-SU-2017:1337-1 and 1 more.