#VU51993 Input validation error in Jenkins and Jenkins LTS - CVE-2021-21639

Vulnerability identifier: #VU51993

Vulnerability risk: Low

CVSSv4.0: 0.6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-21639

CWE-ID: CWE-20

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 compromise the target system.

The vulnerability exists due to the affected software does not validate the type of object created after loading the data submitted to the "config.xml" REST API endpoint of a node. A remote authenticated attacker can replace a node with one of a different type.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Jenkins: 2.0 - 2.286

Jenkins LTS: 1.409.1 - 2.277.1

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External links
https://www.openwall.com/lists/oss-security/2021/04/07/2
https://www.jenkins.io/security/advisory/2021-04-07/#SECURITY-1721

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

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