CVE-2023-39975: 
Kerberos vulnerability analysis and mitigation

MIT Kerberos 5 (krb5) version 1.21 before 1.21.2 contains a double free vulnerability in kdc/do_tgs_req.c. The vulnerability is triggered when an authenticated user can cause an authorization-data handling failure, where incorrect data is copied from one ticket to another (MITRE CVE, NVD Database).

The vulnerability has been assigned a CVSS v3.1 base score of 8.8 (HIGH) with the vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. The issue occurs in the ticket-granting service (TGS) processing where a double free condition can be triggered during authorization-data handling. The vulnerability is classified as CWE-415 (Double Free) and affects MIT Kerberos 5 versions from 1.21 up to (excluding) 1.21.2 (NVD Database).

Successful exploitation of this vulnerability could lead to disclosure of sensitive information, addition or modification of data, or Denial of Service (DoS). The high CVSS score indicates severe potential impacts on confidentiality, integrity, and availability of the affected systems (NetApp Advisory).

The vulnerability has been fixed in MIT Kerberos 5 version 1.21.2. The patch modifies the TGS request processing to copy only the server field from the outer part of the header ticket to the new ticket, instead of copying the whole structure (GitHub Patch).