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Fencer Vulns
high 8.8

CVE-2023-39975 json

kdc/do_tgs_req.c in MIT Kerberos 5 (aka krb5) 1.21 before 1.21.2 has a double free that is reachable if an authenticated user can trigger a…

published 2023-08-16 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-43668

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.5%
EPSS 1.5% chance of exploitation in 30 days, percentile 73%
public exploits
0
none known

Summary

kdc/do_tgs_req.c in MIT Kerberos 5 (aka krb5) 1.21 before 1.21.2 has a double free that is reachable if an authenticated user can trigger an authorization-data handling failure. Incorrect data is copied from one ticket to another.

Patch / fix

  • mit kerberos_5 1.21.2
  • krb5 RHEL 9 1.21.1-1.el9
  • libkadm5 RHEL 9 1.21.1-1.el9
  • krb5-libs RHEL 9 1.21.1-1.el9
  • krb5-pkinit RHEL 9 1.21.1-1.el9
  • krb5-server RHEL 9 1.21.1-1.el9
  • krb5-server-ldap RHEL 9 1.21.1-1.el9
  • krb5-workstation RHEL 9 1.21.1-1.el9

red hat advisories RHSA-2023:6699

  • krb5 openSUSE Tumbleweed 1.21.2-1.1

opensuse advisories openSUSE-SU-2024:13527-1

  • libkadm5 AlmaLinux 9 1.21.1-1.el9
  • krb5-libs AlmaLinux 9 1.21.1-1.el9
  • krb5-pkinit AlmaLinux 9 1.21.1-1.el9
  • krb5-server AlmaLinux 9 1.21.1-1.el9
  • krb5-server-ldap AlmaLinux 9 1.21.1-1.el9
  • krb5-workstation AlmaLinux 9 1.21.1-1.el9

almalinux advisories ALSA-2023:6699

  • krb5 Rocky Linux 9 1.21.1-10.el9_8

rocky linux advisories RLSA-2023:6699

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-39975 updated cvss 8.8

krb5: double-free in KDC TGS processing

  • Red Hat Enterprise Linux AppStream (v. 9) krb5-devel 1.21.1-1.el9, krb5-debuginfo 1.21.1-1.el9, krb5-debugsource 1.21.1-1.el9, libkadm5-debuginfo 1.21.1-1.el9, krb5-libs-debuginfo 1.21.1-1.el9, krb5-pkinit-debuginfo 1.21.1-1.el9, +3 more Red Hat Enterprise Linux BaseOS (v. 9) krb5 1.21.1-1.el9, libkadm5 1.21.1-1.el9, krb5-libs 1.21.1-1.el9, krb5-pkinit 1.21.1-1.el9, krb5-server 1.21.1-1.el9, krb5-server-ldap 1.21.1-1.el9, +1 more
    fixed: vendor fix RHSA-2023:6699
  • Red Hat Enterprise Linux 6 krb5, libkadm5, krb5-libs, krb5-server, krb5-server-ldap, krb5-workstation, +1 more Red Hat Enterprise Linux 7 krb5, libkadm5, krb5-libs, krb5-pkinit, krb5-server, krb5-server-ldap, +1 more Red Hat Enterprise Linux 8 krb5, libkadm5, krb5-libs, krb5-pkinit, krb5-server, krb5-server-ldap, +1 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
2 y ago

Exploit prediction

1.47% chance of exploitation in the next 30 days, higher than 73% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.