CVE-2021-45444

zsh: Prompt expansion vulnerability

Severity Score

7.8

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

In zsh before 5.8.1, an attacker can achieve code execution if they control a command output inside the prompt, as demonstrated by a %F argument. This occurs because of recursive PROMPT_SUBST expansion.

En zsh versiones anteriores a 5.8.1, un atacante puede lograr una ejecución de código si controla la salida de un comando dentro del prompt, como lo demuestra un argumento %F. Esto ocurre debido a la expansión recursiva PROMPT_SUBST

A vulnerability was found in zsh in the parsecolorchar() function of prompt.c file. This flaw allows an attacker to perform code execution if they control a command output inside the prompt, as stated by a %F%K argument. This occurs because of recursive PROMPT_SUBST expansion.

*Credits: N/A

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Network

Attack Complexity

High

Authentication

None

Confidentiality

Partial

Integrity

Partial

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2021-12-21 CVE Reserved
2022-02-13 CVE Published
2024-08-04 CVE Updated
2024-09-19 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection')

CAPEC

References (14)

URL	Tag	Source
http://seclists.org/fulldisclosure/2022/May/33	Mailing List
http://seclists.org/fulldisclosure/2022/May/35	Mailing List
http://seclists.org/fulldisclosure/2022/May/38	Mailing List
https://lists.debian.org/debian-lts-announce/2022/02/msg00020.html	Mailing List
https://support.apple.com/kb/HT213255	Third Party Advisory
https://support.apple.com/kb/HT213256	Third Party Advisory
https://support.apple.com/kb/HT213257	Third Party Advisory
https://vuln.ryotak.me/advisories/63	Third Party Advisory
https://zsh.sourceforge.io/releases.html	Release Notes

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2P3LPMGENEHKDWFO4MWMZSZL6G7Y4CV7	2023-11-07
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BWF3EXNBX5SVFDBL4ZFOD4GJBWFUKWN4	2023-11-07
https://www.debian.org/security/2022/dsa-5078	2023-11-07
https://access.redhat.com/security/cve/CVE-2021-45444	2022-05-10
https://bugzilla.redhat.com/show_bug.cgi?id=2054089	2022-05-10

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Zsh Search vendor "Zsh"		Zsh Search vendor "Zsh" for product "Zsh"				< 5.8.1 Search vendor "Zsh" for product "Zsh" and version " < 5.8.1"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				34 Search vendor "Fedoraproject" for product "Fedora" and version "34"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				35 Search vendor "Fedoraproject" for product "Fedora" and version "35"		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				9.0 Search vendor "Debian" for product "Debian Linux" and version "9.0"		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				10.0 Search vendor "Debian" for product "Debian Linux" and version "10.0"		-		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				11.0 Search vendor "Debian" for product "Debian Linux" and version "11.0"		-		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				>= 10.15 < 10.15.7 Search vendor "Apple" for product "Mac Os X" and version " >= 10.15 < 10.15.7"		-		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.15.7 Search vendor "Apple" for product "Mac Os X" and version "10.15.7"		security_update_2020		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.15.7 Search vendor "Apple" for product "Mac Os X" and version "10.15.7"		security_update_2020-001		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.15.7 Search vendor "Apple" for product "Mac Os X" and version "10.15.7"		security_update_2020-005		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.15.7 Search vendor "Apple" for product "Mac Os X" and version "10.15.7"		security_update_2020-007		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.15.7 Search vendor "Apple" for product "Mac Os X" and version "10.15.7"		security_update_2021-001		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.15.7 Search vendor "Apple" for product "Mac Os X" and version "10.15.7"		security_update_2021-002		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.15.7 Search vendor "Apple" for product "Mac Os X" and version "10.15.7"		security_update_2021-003		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.15.7 Search vendor "Apple" for product "Mac Os X" and version "10.15.7"		security_update_2021-006		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.15.7 Search vendor "Apple" for product "Mac Os X" and version "10.15.7"		security_update_2021-007		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.15.7 Search vendor "Apple" for product "Mac Os X" and version "10.15.7"		security_update_2021-008		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.15.7 Search vendor "Apple" for product "Mac Os X" and version "10.15.7"		security_update_2022-001		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.15.7 Search vendor "Apple" for product "Mac Os X" and version "10.15.7"		security_update_2022-002		Affected
Apple Search vendor "Apple"		Mac Os X Search vendor "Apple" for product "Mac Os X"				10.15.7 Search vendor "Apple" for product "Mac Os X" and version "10.15.7"		security_update_2022-003		Affected
Apple Search vendor "Apple"		Macos Search vendor "Apple" for product "Macos"				>= 11.0 < 11.6.6 Search vendor "Apple" for product "Macos" and version " >= 11.0 < 11.6.6"		-		Affected
Apple Search vendor "Apple"		Macos Search vendor "Apple" for product "Macos"				>= 12.0.0 < 12.4 Search vendor "Apple" for product "Macos" and version " >= 12.0.0 < 12.4"		-		Affected