GNU Bash up to 5.0 Patch 11 shell.c disable_priv_mode dropped privileges

CVSS Meta Temp Score
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CTI Interest Score
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7.9$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as critical, was found in GNU Bash up to 5.0 Patch 11. This affects the function disable_priv_mode of the file shell.c. Such manipulation leads to dropped privileges. This vulnerability is referenced as CVE-2019-18276. It is possible to launch the attack remotely. Furthermore, an exploit is available.

Detailsinfo

A vulnerability was found in GNU Bash up to 5.0 Patch 11 and classified as critical. Affected by this issue is the function disable_priv_mode of the file shell.c. The manipulation with an unknown input leads to a dropped privileges vulnerability. Using CWE to declare the problem leads to CWE-273. The product attempts to drop privileges but does not check or incorrectly checks to see if the drop succeeded. Impacted is confidentiality, integrity, and availability. CVE summarizes:

An issue was discovered in disable_priv_mode in shell.c in GNU Bash through 5.0 patch 11. By default, if Bash is run with its effective UID not equal to its real UID, it will drop privileges by setting its effective UID to its real UID. However, it does so incorrectly. On Linux and other systems that support "saved UID" functionality, the saved UID is not dropped. An attacker with command execution in the shell can use "enable -f" for runtime loading of a new builtin, which can be a shared object that calls setuid() and therefore regains privileges. However, binaries running with an effective UID of 0 are unaffected.

The weakness was published 11/28/2019 (GitHub Repository). The advisory is shared for download at github.com. This vulnerability is handled as CVE-2019-18276 since 10/23/2019. The attack may be launched remotely. A simple authentication is required for exploitation. Technical details as well as a public exploit are known. The MITRE ATT&CK project declares the attack technique as T1068.

The exploit is available at packetstormsecurity.com. It is declared as proof-of-concept.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.3
VulDB Meta Temp Score: 7.9

VulDB Base Score: 8.8
VulDB Temp Score: 7.9
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔍

CVSSv2info

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

NVD Base Score: 🔍

Exploitinginfo

Class: Dropped privileges
CWE: CWE-273 / CWE-266
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔍

Patch: github.com

Timelineinfo

10/23/2019 🔍
11/28/2019 +36 days 🔍
12/19/2019 +21 days 🔍
06/09/2025 +1999 days 🔍

Sourcesinfo

Vendor: gnu.org

Advisory: 155498
Status: Confirmed

CVE: CVE-2019-18276 (🔍)
GCVE (CVE): GCVE-0-2019-18276
GCVE (VulDB): GCVE-100-147380
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 12/19/2019 09:01
Updated: 06/09/2025 21:32
Changes: 12/19/2019 09:01 (39), 12/19/2019 09:06 (17), 03/15/2024 07:17 (5), 06/23/2024 20:46 (22), 06/09/2025 21:32 (13)
Complete: 🔍
Cache ID: 216::103

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