Description
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.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | bash | 5.1~rc1-2 | — |
| Debian 13 | bash | 5.1~rc1-2 | — |
| Debian 12 | bash | 5.1~rc1-2 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | bash | 5.0-6ubuntu1.2 | USN-5380-1 |
| Ubuntu 18.04 LTS | bash | 4.4.18-2ubuntu1.3 | USN-5380-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 16.04 LTS | bash | 4.3-14ubuntu1.4+esm1 | USN-5380-1 |
| Ubuntu Pro 14.04 LTS | bash | 4.3-7ubuntu1.8+esm2 | USN-5380-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | bash +1 | 4.4.19-14.el8 | RHSA-2021:1679 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | bash +1 | 4.4.19-14.el8 | ELSA-2021-1679 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
GitHub 2 repositories
-
M-ensimag/CVE-2019-18276 ★ 3 · Dec 9, 2021
-
SABI-Ensimag/CVE-2019-18276 ★ 0 · Jan 12, 2022
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 9
- SSA-398330 SSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5 Siemens ProductCERT · Oct 13, 2026
- WID-SEC-2025-0227 IBM QRadar SIEM: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 11, 2026
- WID-SEC-2024-0054 IBM Security Verify Access: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jul 16, 2026
- USN-5380-1 bash vulnerability Ubuntu Security Notices (USN) · Jun 29, 2026
- RHSA-2021:1679 Red Hat Security Advisory: bash security and bug fix update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- ICSA-23-348-10 Siemens SIMATIC S7-1500 CISA ICS & IT advisories · Aug 12, 2025
- VDE-2022-010 PHOENIX CONTACT: Multiple Linux component vulnerabilities fixed in latest AXC F x152 LTS release CERT@VDE · May 22, 2025
- ICSA-24-284-16 Rockwell Automation DataMosaix Private Cloud CISA ICS & IT advisories · Oct 10, 2024
- ELSA-2021-1679 Low: bash security and bug fix update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · May 25, 2021
References
- [mina-dev] 20210225 [jira] [Created] (FTPSERVER-500) Security vulnerability in common/lib/log4j-1.2.17.jar mailing-list
- GLSA-202105-34 vendor-advisory
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.youtube.com/watch?v=-wGtxJ8opa8
- https://github.com/bminor/bash/commit/951bdaad7a18cc0dc1036bba86b18b90874d39ff
- http://packetstormsecurity.com/files/155498/Bash-5.0-Patch-11-Privilege-Escalation.html
- https://security.netapp.com/advisory/ntap-20200430-0003/