CVE-2021-4120

snapd could be made to bypass intended access restrictions through snap content interfaces and layout paths

Severity Score

7.8

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

snapd 2.54.2 fails to perform sufficient validation of snap content interface and layout paths, resulting in the ability for snaps to inject arbitrary AppArmor policy rules via malformed content interface and layout declarations and hence escape strict snap confinement. Fixed in snapd versions 2.54.3+18.04, 2.54.3+20.04 and 2.54.3+21.10.1

snapd versión 2.54.2, no lleva a cabo una comprobación suficiente de la interfaz de contenido de snap y de las rutas de diseño, resultando en una posibilidad de que los snaps inyecten reglas de política de AppArmor arbitrarias por medio de declaraciones de interfaz de contenido y de diseño mal formadas y, por tanto, escapen al confinamiento estricto de snap. Corregido en snapd versiones 2.54.3+18.04, 2.54.3+20.04 y 2.54.3+21.10.1

*Credits: Ian Johnson

CVSS Scores

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

Required

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Local

Attack Complexity

Low

Authentication

None

Confidentiality

Partial

Integrity

Partial

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2021-12-14 CVE Reserved
2022-02-17 CVE Published
2024-05-11 EPSS Updated
2024-08-03 CVE Updated
2024-08-03 First Exploit
---------- Exploited in Wild
---------- KEV Due Date

CWE

CWE-20: Improper Input Validation

CAPEC

References (5)

URL	Tag	Source

URL	Date	SRC
http://www.openwall.com/lists/oss-security/2022/02/18/2	2024-08-03
https://bugs.launchpad.net/snapd/+bug/1949368	2024-08-03

URL	Date	SRC
https://ubuntu.com/security/notices/USN-5292-1	2023-11-07

URL	Date	SRC
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3QTBN7LLZISXIA4KU4UKDR27Q5PXDS2U	2023-11-07
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XCGHG6LJAVJJ72TMART6A7N4Z6MSTGI7	2023-11-07

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Canonical Search vendor "Canonical"		Snapd Search vendor "Canonical" for product "Snapd"				<= 2.54.2 Search vendor "Canonical" for product "Snapd" and version " <= 2.54.2"		-		Affected
Canonical Search vendor "Canonical"		Ubuntu Linux Search vendor "Canonical" for product "Ubuntu Linux"				18.04 Search vendor "Canonical" for product "Ubuntu Linux" and version "18.04"		lts		Affected
Canonical Search vendor "Canonical"		Ubuntu Linux Search vendor "Canonical" for product "Ubuntu Linux"				20.04 Search vendor "Canonical" for product "Ubuntu Linux" and version "20.04"		lts		Affected
Canonical Search vendor "Canonical"		Ubuntu Linux Search vendor "Canonical" for product "Ubuntu Linux"				21.10 Search vendor "Canonical" for product "Ubuntu Linux" and version "21.10"		-		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