CVE-2018-13259

Severity: critical (CVSS 9.8 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-09-05 · updated 2026-06-17
Weakness: CWE-20

Description

An issue was discovered in zsh before 5.6. Shebang lines exceeding 64 characters were truncated, potentially leading to an execve call to a program name that is a substring of the intended one.

Affected products

Canonical Ubuntu Linux: 14.04, 16.04, 18.04
zsh: before 5.6 — fixed in 5.6

How to fix

Upgrade to a fixed version: zsh 5.6. Check the vendor advisory for mitigations.

References

https://access.redhat.com/errata/RHSA-2019:2017
https://bugs.debian.org/908000
https://lists.debian.org/debian-lts-announce/2020/12/msg00000.html
https://security.gentoo.org/glsa/201903-02
https://sourceforge.net/p/zsh/code/ci/1c4c7b6a4d17294df028322b70c53803a402233d
https://usn.ubuntu.com/3764-1/
https://www.zsh.org/mla/zsh-announce/136
https://access.redhat.com/errata/RHSA-2019:2017
https://bugs.debian.org/908000
https://lists.debian.org/debian-lts-announce/2020/12/msg00000.html
https://security.gentoo.org/glsa/201903-02
https://sourceforge.net/p/zsh/code/ci/1c4c7b6a4d17294df028322b70c53803a402233d

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