# CVE-2018-20217: libkdb5-9: A Reachable Assertion issue was discovered in the KDC in MIT Kerberos 5 (aka krb5) before 1.17

CVE-2018-20217 is fixed in 20 products on 1 platform, first by krb5-admin-server 1.16-2ubuntu0.3, released December 24, 2022. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2018-20217
- Priority: Routine
- CVSS: n/a (Medium)
- EPSS: 0.0142
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Dec 26, 2018

## Description

A Reachable Assertion issue was discovered in the KDC in MIT Kerberos 5 (aka krb5) before 1.17. If an attacker can obtain a krbtgt ticket using an older encryption type (single-DES, triple-DES, or RC4), the attacker can crash the KDC by making an S4U2Self request.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | krb5-admin-server Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [krb5-admin-server 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-krb5-admin-server-1.16-2ubuntu0.3.md) | Dec 24, 2022 |
| Linux | krb5-gss-samples Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [krb5-gss-samples 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-krb5-gss-samples-1.16-2ubuntu0.3.md) | Dec 24, 2022 |
| Linux | krb5-k5tls Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [krb5-k5tls 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-krb5-k5tls-1.16-2ubuntu0.3.md) | Dec 24, 2022 |
| Linux | krb5-kdc Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [krb5-kdc 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-krb5-kdc-1.16-2ubuntu0.3.md) | Dec 24, 2022 |
| Linux | krb5-kdc-ldap Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [krb5-kdc-ldap 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-krb5-kdc-ldap-1.16-2ubuntu0.3.md) | Dec 24, 2022 |
| Linux | krb5-kpropd Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [krb5-kpropd 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-krb5-kpropd-1.16-2ubuntu0.3.md) | Dec 24, 2022 |
| Linux | krb5-locales Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [krb5-locales 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-krb5-locales-1.16-2ubuntu0.3.md) | Dec 24, 2022 |
| Linux | krb5-multidev Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [krb5-multidev 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-krb5-multidev-1.16-2ubuntu0.3.md) | Dec 24, 2022 |
| Linux | krb5-otp Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [krb5-otp 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-krb5-otp-1.16-2ubuntu0.3.md) | Dec 24, 2022 |
| Linux | krb5-pkinit Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [krb5-pkinit 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-krb5-pkinit-1.16-2ubuntu0.3.md) | Dec 24, 2022 |
| Linux | krb5-user Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [krb5-user 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-krb5-user-1.16-2ubuntu0.3.md) | Dec 24, 2022 |
| Linux | libgssapi-krb5-2 Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [libgssapi-krb5-2 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libgssapi-krb5-2-1.16-2ubuntu0.3.md) | Dec 24, 2022 |
| Linux | libgssrpc4 Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [libgssrpc4 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libgssrpc4-1.16-2ubuntu0.3.md) | Dec 24, 2022 |
| Linux | libk5crypto3 Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [libk5crypto3 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libk5crypto3-1.16-2ubuntu0.3.md) | Dec 24, 2022 |
| Linux | libkadm5clnt-mit11 Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [libkadm5clnt-mit11 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libkadm5clnt-mit11-1.16-2ubuntu0.3.md) | Dec 24, 2022 |
| Linux | libkadm5srv-mit11 Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [libkadm5srv-mit11 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libkadm5srv-mit11-1.16-2ubuntu0.3.md) | Dec 24, 2022 |
| Linux | libkdb5-9 Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [libkdb5-9 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libkdb5-9-1.16-2ubuntu0.3.md) | Dec 24, 2022 |
| Linux | libkrad0 Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [libkrad0 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libkrad0-1.16-2ubuntu0.3.md) | Dec 24, 2022 |
| Linux | libkrb5-3 Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [libkrb5-3 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libkrb5-3-1.16-2ubuntu0.3.md) | Dec 24, 2022 |
| Linux | libkrb5support0 Ubuntu 18.04.6 LTS (bionic) | 1.16-2ubuntu0.3 | [libkrb5support0 1.16-2ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libkrb5support0-1.16-2ubuntu0.3.md) | Dec 24, 2022 |

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