Stack-based buffer overflow in zsh
Priority LOW 25CWE-121Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 10 fixed, 2 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-121 and the CVSS impact.
Summary
zsh through version 5.4.2 is vulnerable to a stack-based buffer overflow in the exec.c:hashcmd() function. A local attacker could exploit this to cause a denial of service.
Why it matters now
EPSS 0.00428 37th percentileScored 2026-11-07
Fix Partial Red Hat: 1 advisoryRed Hat: 10 fixed, 2 without a fix
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| zsh | zsh | 5.4.2 | — | No fix listed | CNA |
- zsh Vendorzsh Affected 5.4.2 Fixed in — No fix listed CNA
CPE configurations NVD · 8
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:zsh:zsh:*:*:*:*:*:*:*:* | up to 5.4.2 | Vulnerable | zsh |
| cpe:2.3:o:debian:debian_linux:7.0:*:*:*:*:*:*:* | 7.0 | Vulnerable | Debian |
| cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:* | 14.04 | Vulnerable | Canonical |
| cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:* | 16.04 | Vulnerable | Canonical |
| cpe:2.3:o:canonical:ubuntu_linux:17.10:*:*:*:*:*:*:* | 17.10 | Vulnerable | Canonical |
| cpe:2.3:o:redhat:enterprise_linux_desktop:7.0:*:*:*:*:*:*:* | 7.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:* | 7.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_workstation:7.0:*:*:*:*:*:*:* | 7.0 | Vulnerable | Red Hat |
- cpe:2.3:a:zsh:zsh:*:*:*:*:*:*:*:* Versions up to 5.4.2 Vulnerable ·zsh
- cpe:2.3:o:debian:debian_linux:7.0:*:*:*:*:*:*:* Versions 7.0 Vulnerable ·Debian
- cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:* Versions 14.04 Vulnerable ·Canonical
- cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:* Versions 16.04 Vulnerable ·Canonical
- cpe:2.3:o:canonical:ubuntu_linux:17.10:*:*:*:*:*:*:* Versions 17.10 Vulnerable ·Canonical
- cpe:2.3:o:redhat:enterprise_linux_desktop:7.0:*:*:*:*:*:*:* Versions 7.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:* Versions 7.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_workstation:7.0:*:*:*:*:*:*:* Versions 7.0 Vulnerable ·Red Hat
Remediation
Red Hat 1 advisory
- RHSA-2018:3073 Released 2018-10-30 · Red Hat rating Moderatezsh security and bug fix update
- Red Hat Enterprise Linux Client (v. 7) zsh-5.0.2-31.el7
- Red Hat Enterprise Linux Client Optional (v. 7) zsh-html-5.0.2-31.el7
- Red Hat Enterprise Linux ComputeNode (v. 7) zsh-5.0.2-31.el7
- Red Hat Enterprise Linux ComputeNode Optional (v. 7) zsh-html-5.0.2-31.el7
- Red Hat Enterprise Linux Server (v. 7) zsh-5.0.2-31.el7
- Red Hat Enterprise Linux Server Optional (v. 7) zsh-html-5.0.2-31.el7
- Red Hat Enterprise Linux Workstation (v. 7) zsh-5.0.2-31.el7
- Red Hat Enterprise Linux Workstation Optional (v. 7) zsh-html-5.0.2-31.el7
- Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server (v. 7) zsh-5.0.2-31.el7
- Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server Optional (v. 7) zsh-html-5.0.2-31.el7
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 5 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise Linux Client (v. 7) | Fixed | RHSA-2018:3073 |
| Red Hat Enterprise Linux Client Optional (v. 7) | Fixed | RHSA-2018:3073 |
| Red Hat Enterprise Linux ComputeNode (v. 7) | Fixed | RHSA-2018:3073 |
| Red Hat Enterprise Linux ComputeNode Optional (v. 7) | Fixed | RHSA-2018:3073 |
| Red Hat Enterprise Linux Server (v. 7) | Fixed | RHSA-2018:3073 |
| Red Hat Enterprise Linux Server Optional (v. 7) | Fixed | RHSA-2018:3073 |
| Red Hat Enterprise Linux Workstation (v. 7) | Fixed | RHSA-2018:3073 |
| Red Hat Enterprise Linux Workstation Optional (v. 7) | Fixed | RHSA-2018:3073 |
| Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server (v. 7) | Fixed | RHSA-2018:3073 |
| Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server Optional (v. 7) | Fixed | RHSA-2018:3073 |
Not affected: 1 product
- Red Hat Enterprise Linux 8
Timeline
- 2026-10-02 Threatist record created from CVE-2018-1071
- 2026-10-03 Alias added: GHSA-xc49-qj7m-vpp4
References
More Zsh vulnerabilities
- TI-2017-13391 In utils.c in zsh before 5.4, symlink expansion had a buffer overflow. CVSS 3.0CRITICAL 9.8
- TI-2018-09527 Improper input validation in zsh before 5.6 CVSS 3.0CRITICAL 9.8
- TI-2018-05456 In subst.c in zsh through 5.4.2, there is a NULL pointer dereference when using ${(PA)...} on an empty array result. CVSS 3.0CRITICAL 9.8
- TI-2018-00459 Improper input validation in zsh before 5.6 CVSS 3.0CRITICAL 9.8
- TI-2014-08227 In exec.c in zsh before 5.0.7, there is a buffer overflow for very long fds in the ">& fd" syntax. CVSS 3.0CRITICAL 9.8
- TI-2016-08755 In zsh before 5.3, an off-by-one error resulted in undersized buffers that were intended to support PATH_MAX characters. CVSS 3.0CRITICAL 9.8
Sources
- CVE-2018-1071 · CVE Program
- CVE-2018-1071 · NVD
- FIRST EPSS
- GHSA-xc49-qj7m-vpp4 · GitHub Advisory Database · CC BY 4.0
- CVE-2018-1071 · Red Hat security data · CC BY 4.0
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