---
id: CVE-2021-37750
title: >-
  The Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) before 1.18.5
  and 1.19.x before 1.19.3 has a NULL pointer dereference in kdc/do_tgs_req.c
  via a FAST inner body that lacks a server field.
summary: >-
  The Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) before 1.18.5
  and 1.19.x before 1.19.3 has a NULL pointer dereference in kdc/do_tgs_req.c
  via a FAST inner body that lacks a server field.
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-476
vendor: mit
product: kerberos_5
affected:
  - kerberos_5 < 1.18.5
  - 'kerberos_5 >= 1.19.0, < 1.19.3'
  - fedora = 33
  - debian_linux = 9.0
  - starwind_virtual_san = v8r13
  - communications_cloud_native_core_network_slice_selection_function = 22.1.0
patched:
  - kerberos_5 1.19.3
published: '2021-08-23'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T12:17:15.293'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-37750'
references:
  - url: >-
      https://github.com/krb5/krb5/commit/d775c95af7606a51bf79547a94fa52ddd1cb7f49
    label: cve@mitre.org
  - url: 'https://github.com/krb5/krb5/releases'
    label: cve@mitre.org
  - url: 'https://lists.debian.org/debian-lts-announce/2021/09/msg00019.html'
    label: cve@mitre.org
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MFCLW7D46E4VCREKKH453T5DA4XOLHU2/
    label: cve@mitre.org
  - url: 'https://security.netapp.com/advisory/ntap-20210923-0002/'
    label: cve@mitre.org
  - url: 'https://web.mit.edu/kerberos/advisories/'
    label: cve@mitre.org
  - url: 'https://www.oracle.com/security-alerts/cpujul2022.html'
    label: cve@mitre.org
  - url: 'https://www.starwindsoftware.com/security/sw-20220817-0004/'
    label: cve@mitre.org
  - url: >-
      https://github.com/krb5/krb5/commit/d775c95af7606a51bf79547a94fa52ddd1cb7f49
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://github.com/krb5/krb5/releases'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://lists.debian.org/debian-lts-announce/2021/09/msg00019.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MFCLW7D46E4VCREKKH453T5DA4XOLHU2/
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://security.netapp.com/advisory/ntap-20210923-0002/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://web.mit.edu/kerberos/advisories/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.oracle.com/security-alerts/cpujul2022.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.starwindsoftware.com/security/sw-20220817-0004/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-398330.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
epss: 0.02166
epssPercentile: 0.81787
ingestedAt: '2026-10-14T12:29:10.825Z'
---

## Overview

The Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) before 1.18.5 and 1.19.x before 1.19.3 has a NULL pointer dereference in kdc/do_tgs_req.c via a FAST inner body that lacks a server field.

## Affected

- `kerberos_5 < 1.18.5`
- `kerberos_5 >= 1.19.0, < 1.19.3`
- `fedora = 33`
- `debian_linux = 9.0`
- `starwind_virtual_san = v8r13`
- `communications_cloud_native_core_network_slice_selection_function = 22.1.0`

## Remediation

Upgrade past the affected range:

- `kerberos_5 1.19.3`