Vulnerability identifier: #VU57978

Vulnerability risk: High

CVSSv3.1: 7.8 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-21685

CWE-ID: CWE-862

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Jenkins
Server applications / Application servers
Jenkins LTS
Server applications / Application servers

Vendor: Jenkins

Description

The vulnerability allows a remote attacker to bypass authorization checks.

The vulnerability exists due to the affected application does not check agent-to-controller access to create parent directories in FilePath#mkdirs. A remote attacker can read and write arbitrary files on the Jenkins controller file system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Jenkins: 2.0 - 2.318

Jenkins LTS: 1.409.1 - 2.303.2

---

External links
http://jenkins.io/security/advisory/2021-11-04/

---

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.