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Fencer Vulns
critical 9.8

CVE-2018-7548 json

In subst.c in zsh through 5.4.2, there is a NULL pointer dereference when using ${(PA)...} on an empty array result.

published 2018-02-27 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-19275

cvss
9.8
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.5%
EPSS 2.5% chance of exploitation in 30 days, percentile 85%
public exploits
0
none known

Summary

In subst.c in zsh through 5.4.2, there is a NULL pointer dereference when using ${(PA)...} on an empty array result.

Patch / fix

  • zsh Debian 14, Debian 13, Debian 12 5.5-1

debian advisories DEBIAN-CVE-2018-7548

  • zsh Arch Linux 5.5-1

arch linux advisories AVG-642

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-7548 updated cvss 2.8

zsh: null-pointer deref when using ${(PA)...} on an empty array result

  • Red Hat Enterprise Linux 5 zsh Red Hat Enterprise Linux 6 zsh, zsh-html Red Hat Enterprise Linux 7 zsh, zsh-html Red Hat Enterprise Linux 8 zsh, zsh-html
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.54% chance of exploitation in the next 30 days, higher than 85% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.0 9.8 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.