CVE-2023-49284

What it is

fish is a smart and user-friendly command line shell for macOS, Linux, and the rest of the family. fish shell uses certain Unicode non-characters internally for marking wildcards and expansions. It will incorrectly allow these markers to be read on command substitution output, rather than transforming them into a safe internal representation. While this may cause unexpected behavior with direct input (for example, echo \UFDD2HOME has the same output as echo $HOME), this may become a minor security problem if the output is being fed from an external program into a command substitution where this output may not be expected. This design flaw was introduced in very early versions of fish, predating the version control system, and is thought to be present in every version of fish released in the last 15 years or more, although with different characters. Code execution does not appear to be possible, but denial of service (through large brace expansion) or information disclosure (such as variable expansion) is potentially possible under certain circumstances. fish shell 3.6.2 has been released to correct this issue. Users are advised to upgrade. There are no known workarounds for this vulnerability.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account, but needs a user to act. Limited direct impact.

Exploit odds

0.5% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2023-12-05 00:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 06:35 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.5% in the next 30 days (EPSS).
• Severity: 3.9 LOW (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2023-12-05 00:15 UTC

Last modified

2026-06-17 06:35 UTC

Exploit probability

0.5% · EPSS, next 30 days

Weakness

CWE-436

Record status

Modified

Affected

• Fishshell Fish < 3.6.2

Attack profile CVSS 3.1 · 3.9

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

Required

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

Low

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2023-49284.md and follow it. Check whether this project is affected by CVE-2023-49284. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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