CVE-2017-18205

Severity: high (CVSS 8.1 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-02-27 · updated 2026-06-17
Weakness: CWE-476

Description

In builtin.c in zsh before 5.4, when sh compatibility mode is used, there is a NULL pointer dereference during processing of the cd command with no argument if HOME is not set.

Affected products

Zsh Project Zsh: before 5.4 — fixed in 5.4

How to fix

Upgrade to a fixed version: Zsh Project Zsh 5.4. Check the vendor advisory for mitigations.

References

https://access.redhat.com/errata/RHSA-2018:3073
https://security.gentoo.org/glsa/201805-10
https://sourceforge.net/p/zsh/code/ci/eb783754bdb74377f3cea4ceca9c23a02ea1bf58
https://usn.ubuntu.com/3593-1/
https://access.redhat.com/errata/RHSA-2018:3073
https://security.gentoo.org/glsa/201805-10
https://sourceforge.net/p/zsh/code/ci/eb783754bdb74377f3cea4ceca9c23a02ea1bf58
https://usn.ubuntu.com/3593-1/

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