CVE-2021-21686

jenkins: File path filters do not canonicalize paths, allowing operations to follow symbolic links to outside allowed directories

Severity Score

8.1

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

File path filters in the agent-to-controller security subsystem of Jenkins 2.318 and earlier, LTS 2.303.2 and earlier do not canonicalize paths, allowing operations to follow symbolic links to outside allowed directories.

Los filtros de rutas de archivos en el subsistema de seguridad agente-a-controlador de Jenkins versiones 2.318 y anteriores, LTS versiones 2.303.2 y anteriores, no canonizan las rutas, permitiendo que las operaciones sigan enlaces simbólicos a directorios no permitidos

A link following vulnerability was found in Jenkins. The file path filters do not canonicalize paths allowing operations to follow symbolic links to directories they are not supposed to have access to. This may allow an attacker to read and write arbitrary files on the Jenkins controller file system.

*Credits: N/A

CVSS Scores

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Network

Attack Complexity

Medium

Authentication

None

Confidentiality

Partial

Integrity

Partial

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2021-01-04 CVE Reserved
2021-11-04 CVE Published
2024-07-20 EPSS Updated
2024-08-03 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-59: Improper Link Resolution Before File Access ('Link Following')

CAPEC

References (3)

URL	Tag	Source

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC
https://www.jenkins.io/security/advisory/2021-11-04/#SECURITY-2455	2023-11-22
https://access.redhat.com/security/cve/CVE-2021-21686	2021-11-29
https://bugzilla.redhat.com/show_bug.cgi?id=2020323	2021-11-29

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Jenkins Search vendor "Jenkins"		Jenkins Search vendor "Jenkins" for product "Jenkins"				< 2.303.3 Search vendor "Jenkins" for product "Jenkins" and version " < 2.303.3"		lts		Affected
Jenkins Search vendor "Jenkins"		Jenkins Search vendor "Jenkins" for product "Jenkins"				< 2.319 Search vendor "Jenkins" for product "Jenkins" and version " < 2.319"		-		Affected