GNU Bash popd use after free

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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5.3$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as critical, was found in GNU Bash. The affected element is an unknown function of the component popd. Executing a manipulation can lead to use after free. This vulnerability is registered as CVE-2016-9401. The attack needs to be launched locally. No exploit is available. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in GNU Bash (affected version not known). This vulnerability affects some unknown functionality of the component popd. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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

The bug was discovered 11/17/2016. The weakness was published 01/23/2017 (Website). The advisory is shared for download at openwall.com. This vulnerability was named CVE-2016-9401 since 11/17/2016. The attack needs to be approached locally. A single authentication is required for exploitation. There are neither technical details nor an exploit publicly available.

The vulnerability was handled as a non-public zero-day exploit for at least 45 days. During that time the estimated underground price was around $5k-$25k. The vulnerability scanner Nessus provides a plugin with the ID 96233 (GLSA-201701-02 : Bash: Multiple vulnerabilities), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Gentoo Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 176754 (Debian Security Update for bash (DLA 1726-1)).

Upgrading eliminates this vulnerability. A possible mitigation has been published even before and not after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (96233) and SecurityFocus (BID 94398†). Similar entries are available at VDB-95737 and VDB-132122. Once again VulDB remains the best source for vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.4
VulDB Meta Temp Score: 5.3

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔍

CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: No

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 96233
Nessus Name: GLSA-201701-02 : Bash: Multiple vulnerabilities
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 871165
OpenVAS Name: RedHat Update for bash RHSA-2017:1931-01
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Timelineinfo

11/17/2016 🔍
11/17/2016 +0 days 🔍
11/17/2016 +0 days 🔍
01/01/2017 +45 days 🔍
01/03/2017 +2 days 🔍
01/23/2017 +20 days 🔍
01/23/2017 +0 days 🔍
01/24/2017 +1 days 🔍
08/07/2025 +3116 days 🔍

Sourcesinfo

Vendor: gnu.org

Advisory: RHSA-2017:1931
Status: Confirmed

CVE: CVE-2016-9401 (🔍)
GCVE (CVE): GCVE-0-2016-9401
GCVE (VulDB): GCVE-100-95860
SecurityFocus: 94398 - GNU Bash CVE-2016-9401 Local Security Bypass Vulnerability
OSVDB: - CVE-2016-9401 - bash - Security Bypass Issue

See also: 🔍

Entryinfo

Created: 01/24/2017 08:33
Updated: 08/07/2025 00:26
Changes: 01/24/2017 08:33 (73), 07/30/2020 17:38 (7), 11/03/2022 09:49 (3), 11/03/2022 09:51 (1), 08/07/2025 00:26 (15)
Complete: 🔍
Cache ID: 216:A08:103

Once again VulDB remains the best source for vulnerability data.

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