# CVE-2019-17455: libntlm0: Libntlm through 1.5 relies on a fixed buffer size for tSmbNtlmAuthRequest, tSmbNtlmAuthChallenge, and tSmbNtlmAuthRes...

CVE-2019-17455 is fixed in libntlm0 on 1 platform, first by libntlm0 1.4-8ubuntu0.1, released October 10, 2019. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2019-17455
- Priority: Routine
- CVSS: n/a (Medium)
- EPSS: 0.0311
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 10, 2019

## Description

Libntlm through 1.5 relies on a fixed buffer size for tSmbNtlmAuthRequest, tSmbNtlmAuthChallenge, and tSmbNtlmAuthResponse read and write operations, as demonstrated by a stack-based buffer over-read in buildSmbNtlmAuthRequest in smbutil.c for a crafted NTLM request.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libntlm0 Ubuntu 18.04.6 LTS (bionic) | 1.4-8ubuntu0.1 | [libntlm0 1.4-8ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libntlm0-1.4-8ubuntu0.1.md) | Oct 10, 2019 |
| Linux | libntlm0 Ubuntu 20.04 LTS (focal) | 1.5-2ubuntu0.1 | [libntlm0 1.5-2ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libntlm0-1.5-2ubuntu0.1.md) | Oct 10, 2019 |

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Data as of 2026-11-07T06:34:28Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo