#VU57979 Path traversal in Jenkins and Jenkins LTS - CVE-2021-21686

Vulnerability identifier: #VU57979

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-21686

CWE-ID: CWE-22

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 perform directory traversal attacks.

The vulnerability exists due to file path filters do not canonicalize paths. A remote attacker can send a specially crafted HTTP request and read arbitrary files on the system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Jenkins: 2.0 - 2.318

Jenkins LTS: 1.409.1 - 2.303.2

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

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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.