Jenkins 2.333 and earlier, LTS 2.319.2 and earlier defines custom XStream converters that have not been updated to apply the protections for the vulnerability CVE-2021-43859 and allow unconstrained resource usage.
https://www.jenkins.io/security/advisory/2022-02-09/#SECURITY-2602
Source: MITRE
Published: 2022-02-09
Updated: 2022-02-11
Type: CWE-502
Base Score: 5
Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P
Impact Score: 2.9
Exploitability Score: 10
Severity: MEDIUM
Base Score: 7.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Impact Score: 3.6
Exploitability Score: 3.9
Severity: HIGH