CVE-2021-3726Network attack vector

Command execution via prompt expansion in title

Published Nov 30, 2021 · Updated Aug 3, 2024

OS command injection in the title function in Oh My Zsh before a263cdac allows attackers to execute shell commands via crafted input. The function enables prompt substitution and passes its arguments to print -P, causing untrusted prompt syntax to be expanded during terminal-title output. Exploitation requires custom user code to supply unsanitized attacker-controlled data; default Oh My Zsh calls are safe, and commands run with the shell process's privileges.

CVSS severity7.5
High
EPSS probability0.78%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

OS command injection in the title function in Oh My Zsh before a263cdac allows attackers to execute shell commands via crafted input. The function enables prompt substitution and passes its arguments to print -P, causing untrusted prompt syntax to be expanded during terminal-title output. Exploitation requires custom user code to supply unsanitized attacker-controlled data; default Oh My Zsh calls are safe, and commands run with the shell process's privileges.

The record

CVE
CVE-2021-3726
Published
Nov 30, 2021
Updated
Aug 3, 2024
Vendor
Oh My Zsh
Product
Oh My Zsh
Classifications
CWE-78, T1059.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 30, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <a263cdac

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Oh My Zsh · Oh My Zshversion=unspecified <a263cdac

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
7.5huntr.devCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059.004Command and Scripting Interpreter: Unix Shell

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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