How severe is CVE-2017-18205?

CVE-2017-18205 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2017-18205 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (79th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-18205?

CVE-2017-18205 affects Zsh Project Zsh. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2017-18205?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2017-18205 published?

CVE-2017-18205 was published on 2018-02-27 and last updated on 2026-06-17.

CVE-2017-18205

CVE-2017-18205 is a high-severity vulnerability in Zsh Project Zsh with a CVSS 3.x base score of 8.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Severity: High (CVSS 3.x base score 8.1)
CVSS v2: 6.8
EPSS exploit prediction: 2% (79th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Zsh Project Zsh
Published: 2018-02-27
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2017-18205?: 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.
How severe is CVE-2017-18205?: CVE-2017-18205 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2017-18205 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (79th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-18205?: CVE-2017-18205 affects Zsh Project Zsh. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2017-18205?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2017-18205 published?: CVE-2017-18205 was published on 2018-02-27 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:zsh_project:zsh:*:*:*:*:*:*:*:*

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