#VU10873 NULL pointer dereference in zsh - CVE-2018-7548

Vulnerability identifier: #VU10873

Vulnerability risk: Low

CVSSv4.0: 1.1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2018-7548

CWE-ID: CWE-476

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
zsh
Client/Desktop applications / Software for system administration

Vendor: SourceForge

Description
The vulnerability allows a local attacker to cause DoS condition on the target system.

The weakness exists in the subst.c source code file due to a NULL pointer dereference. A local attacker can implement ${(PA)...} characters on an empty array result, trigger a NULL pointer dereference condition and cause the service to crash.

Mitigation
Install update from vendor's website.

Vulnerable software versions

zsh: 5.0.0 - 5.4.2

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External links
https://sourceforge.net/p/zsh/code/ci/110b13e1090bc31ac1352b28adc2d02b6d25a102

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.