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CVE-2018-7548

29
FAUCET Score

CVE-2018-7548 describes a NULL pointer dereference vulnerability in zsh through version 5.4.2, specifically within the subst.c file when using ${(PA)...} on an empty array result. This critical vulnerability, with a CVSS score of 9.8, allows for remote exploitation with low attack complexity, potentially leading to high impacts on confidentiality, integrity, and availability. Despite its severity, there is no evidence of active exploitation, no known public exploit code (Metasploit, Nuclei, ExploitDB), and minimal community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
<= 5.4.2CPE matchmatch criteria
cpe:2.3:a:zsh:zsh:*:*:*:*:*:*:*:*
17.10CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:17.10:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

9.8CRITICAL

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.0

Exploit Intelligence

EPSS Score
2.59%
Probability of exploitation in next 30 days
EPSS Percentile
83.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0259 is in the 74th percentile among its peer group of 36,833 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Advisories (1)

redhatCVE-2018-7548Low

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

Mar 24, 2017

References

security.gentoo.org / glsa/201805-10
Third Party Advisory
sourceforge.net / p/zsh/code/ci/110b13e1090bc31ac1352b28adc2d02b6d25a102
PatchThird Party Advisory
usn.ubuntu.com / 3593-1
Third Party Advisory