What’s Vulnerable › Vulnerabilities

CVE-2016-9401

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2017-01-23 · updated 2026-06-17
• Weakness: CWE-416

Description

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

Affected products

• Debian Linux: 8.0
• GNU Bash: before 4.4; 4.4-patch1, 4.4-patch2, 4.4-patch3, 4.4-patch4, 4.4-patch5 — fixed in 4.4
• RedHat Enterprise Linux Desktop: 6.0, 7.0
• RedHat Enterprise Linux Server: 6.0, 7.0
• RedHat Enterprise Linux Server Aus: 7.4, 7.6, 7.7
• RedHat Enterprise Linux Server Eus: 7.4, 7.5, 7.6, 7.7
• RedHat Enterprise Linux Server Tus: 7.6, 7.7
• RedHat Enterprise Linux Workstation: 6.0, 7.0

How to fix

Upgrade to a fixed version: GNU Bash 4.4. Check the vendor advisory for mitigations.

References

• http://rhn.redhat.com/errata/RHSA-2017-0725.html
• http://www.openwall.com/lists/oss-security/2016/11/17/5
• http://www.openwall.com/lists/oss-security/2016/11/17/9
• http://www.securityfocus.com/bid/94398
• https://access.redhat.com/errata/RHSA-2017:1931
• https://lists.debian.org/debian-lts-announce/2019/03/msg00028.html
• https://security.gentoo.org/glsa/201701-02
• http://rhn.redhat.com/errata/RHSA-2017-0725.html
• http://www.openwall.com/lists/oss-security/2016/11/17/5
• http://www.openwall.com/lists/oss-security/2016/11/17/9
• http://www.securityfocus.com/bid/94398
• https://access.redhat.com/errata/RHSA-2017:1931

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