# CVE-2021-44758: libkdc2-heimdal: Heimdal before 7.7.1 allows attackers to cause a NULL pointer dereference in a SPNEGO acceptor via a preferred_mech_t...

CVE-2021-44758 is fixed in 23 products on 1 platform, first by heimdal-clients 7.5.0+dfsg-1ubuntu0.3, released December 25, 2022. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2021-44758
- Priority: High
- CVSS: 7.5 (Medium)
- EPSS: 0.0133
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Dec 25, 2022

## Description

Heimdal before 7.7.1 allows attackers to cause a NULL pointer dereference in a SPNEGO acceptor via a preferred_mech_type of GSS_C_NO_OID and a nonzero initial_response value to send_accept.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | heimdal Debian 12.15 (bookworm) | 7.8.git20221115.a6cf945+dfsg-1 | [DEBIAN-CVE-2021-44758](https://patchblox.com/security/data/fix/linux/debian-cve-2021-44758.md) | Dec 26, 2022 |
| Linux | heimdal Debian 13.5 (trixie) | 7.8.git20221115.a6cf945+dfsg-1 | [DEBIAN-CVE-2021-44758](https://patchblox.com/security/data/fix/linux/debian-cve-2021-44758.md) | Dec 26, 2022 |
| Linux | heimdal Debian 14 | 7.8.git20221115.a6cf945+dfsg-1 | [DEBIAN-CVE-2021-44758](https://patchblox.com/security/data/fix/linux/debian-cve-2021-44758.md) | Dec 26, 2022 |
| Linux | heimdal-clients Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [heimdal-clients 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-heimdal-clients-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | heimdal-clients Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [heimdal-clients 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-heimdal-clients-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | heimdal-docs Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [heimdal-docs 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-heimdal-docs-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | heimdal-docs Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [heimdal-docs 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-heimdal-docs-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | heimdal-kcm Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [heimdal-kcm 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-heimdal-kcm-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | heimdal-kcm Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [heimdal-kcm 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-heimdal-kcm-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | heimdal-kdc Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [heimdal-kdc 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-heimdal-kdc-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | heimdal-kdc Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [heimdal-kdc 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-heimdal-kdc-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | heimdal-multidev Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [heimdal-multidev 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-heimdal-multidev-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | heimdal-multidev Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [heimdal-multidev 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-heimdal-multidev-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | heimdal-servers Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [heimdal-servers 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-heimdal-servers-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | heimdal-servers Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [heimdal-servers 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-heimdal-servers-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | libasn1-8-heimdal Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [libasn1-8-heimdal 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libasn1-8-heimdal-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | libasn1-8-heimdal Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [libasn1-8-heimdal 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libasn1-8-heimdal-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | libgssapi3-heimdal Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [libgssapi3-heimdal 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libgssapi3-heimdal-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | libgssapi3-heimdal Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [libgssapi3-heimdal 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libgssapi3-heimdal-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | libhcrypto4-heimdal Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [libhcrypto4-heimdal 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libhcrypto4-heimdal-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | libhcrypto4-heimdal Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [libhcrypto4-heimdal 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libhcrypto4-heimdal-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | libhdb9-heimdal Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [libhdb9-heimdal 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libhdb9-heimdal-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | libhdb9-heimdal Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [libhdb9-heimdal 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libhdb9-heimdal-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | libheimbase1-heimdal Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [libheimbase1-heimdal 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libheimbase1-heimdal-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | libheimbase1-heimdal Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [libheimbase1-heimdal 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libheimbase1-heimdal-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | libheimntlm0-heimdal Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [libheimntlm0-heimdal 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libheimntlm0-heimdal-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | libheimntlm0-heimdal Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [libheimntlm0-heimdal 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libheimntlm0-heimdal-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | libhx509-5-heimdal Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [libhx509-5-heimdal 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libhx509-5-heimdal-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | libhx509-5-heimdal Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [libhx509-5-heimdal 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libhx509-5-heimdal-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | libkadm5clnt7-heimdal Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [libkadm5clnt7-heimdal 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libkadm5clnt7-heimdal-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | libkadm5clnt7-heimdal Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [libkadm5clnt7-heimdal 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libkadm5clnt7-heimdal-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | libkadm5srv8-heimdal Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [libkadm5srv8-heimdal 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libkadm5srv8-heimdal-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | libkadm5srv8-heimdal Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [libkadm5srv8-heimdal 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libkadm5srv8-heimdal-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | libkafs0-heimdal Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [libkafs0-heimdal 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libkafs0-heimdal-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | libkafs0-heimdal Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [libkafs0-heimdal 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libkafs0-heimdal-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | libkdc2-heimdal Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [libkdc2-heimdal 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libkdc2-heimdal-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | libkdc2-heimdal Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [libkdc2-heimdal 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libkdc2-heimdal-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | libkrb5-26-heimdal Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [libkrb5-26-heimdal 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libkrb5-26-heimdal-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | libkrb5-26-heimdal Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [libkrb5-26-heimdal 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libkrb5-26-heimdal-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | libotp0-heimdal Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [libotp0-heimdal 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libotp0-heimdal-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | libotp0-heimdal Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [libotp0-heimdal 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libotp0-heimdal-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | libroken18-heimdal Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [libroken18-heimdal 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libroken18-heimdal-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | libroken18-heimdal Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [libroken18-heimdal 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libroken18-heimdal-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | libsl0-heimdal Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [libsl0-heimdal 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libsl0-heimdal-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | libsl0-heimdal Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [libsl0-heimdal 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libsl0-heimdal-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |
| Linux | libwind0-heimdal Ubuntu 18.04.6 LTS (bionic) | 7.5.0+dfsg-1ubuntu0.3 | [libwind0-heimdal 7.5.0+dfsg-1ubuntu0.3](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libwind0-heimdal-7.5.0-dfsg-1ubuntu0.3.md) | Dec 25, 2022 |
| Linux | libwind0-heimdal Ubuntu 20.04 LTS (focal) | 7.7.0+dfsg-1ubuntu1.3 | [libwind0-heimdal 7.7.0+dfsg-1ubuntu1.3](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libwind0-heimdal-7.7.0-dfsg-1ubuntu1.3.md) | Dec 25, 2022 |

---

Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.