libntlm: stack-based buffer overflow in buildSmbNtlmAuthRequest in smbutil.c
Published Oct 10, 2019
9.8
CRITICALCVSS 3.1
EPSS 3.11%
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.
Affected products
No data.
Configuration 2
- 8.0
- 9.0
Configuration 3
- 14.04
- 16.04
- 18.04
- 20.04
Configuration 4
- 32
- 33
Configuration 5
- 15.0
- 15.1
No data.
Red Hat Enterprise Linux 6
libntlm
Will not fix
Red Hat Enterprise Linux 7
libntlm
Affected
Red Hat Satellite 5
libntlm
Out of support scope
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 6 | libntlm | Will not fix | n/a |
| Red Hat Enterprise Linux 7 | libntlm | Affected | n/a |
| Red Hat Satellite 5 | libntlm | Out of support scope | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
The vulnerability is rated Medium because no package in Red Hat Enterprise Linux versions 6 and 7 is using Libntlm. Most 3rd party applications using Libntlm are command line clients and would be affected via a command line option or a configuration file, which are local vectors.
Red Hat mitigation
The calling application must verify that the input username and domain fit in the 1024 byte buffer.
Metrics
No CVSS v4.0 score for this CVE.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
1 other source (Red Hat) ▾
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
No CVSS v3.0 score for this CVE.
AV:N/AC:L/Au:N/C:P/I:P/A:P
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 2, 2026.
Score over time
2021–2026- EPSS v1
- EPSS v5
- EPSS v2
- EPSS v3
- EPSS v4
Percentile over time
- EPSS v1
- EPSS v5
- EPSS v2
- EPSS v3
- EPSS v4
Table of values (27 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 2, 2026 | 3.11% (0.03107) | 87.33th | v5 (v2026.06.15) |
| Jun 15, 2026 | 3.11% (0.03107) | 86.03th | v5 (v2026.06.15) |
| Dec 28, 2025 | 7.08% (0.07078) | 91.20th | v4 (v2025.03.14) |
| Dec 27, 2025 | 3.93% (0.03934) | 88.02th | v4 (v2025.03.14) |
| Nov 21, 2025 | 7.08% (0.07078) | 91.13th | v4 (v2025.03.14) |
| Nov 18, 2025 | 8.17% (0.08167) | 91.31th | v4 (v2025.03.14) |
| Oct 28, 2025 | 7.08% (0.07078) | 91.09th | v4 (v2025.03.14) |
| Oct 27, 2025 | 3.93% (0.03934) | 87.85th | v4 (v2025.03.14) |
| Oct 1, 2025 | 7.08% (0.07078) | 91.19th | v4 (v2025.03.14) |
| Mar 30, 2025 | 4.63% (0.04635) | 88.27th | v4 (v2025.03.14) |
| Mar 29, 2025 | 8.60% (0.08595) | 87.16th | v4 (v2025.03.14) |
| Mar 17, 2025 | 4.63% (0.04635) | 88.56th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.63% (0.00626) | 79.66th | v3 (v2023.03.01) |
| May 3, 2024 | 0.63% (0.00626) | 78.83th | v3 (v2023.03.01) |
| Feb 3, 2024 | 0.63% (0.00626) | 76.79th | v3 (v2023.03.01) |
| Nov 8, 2023 | 0.63% (0.00634) | 76.71th | v3 (v2023.03.01) |
| Sep 3, 2023 | 0.45% (0.00448) | 71.85th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.52% (0.00521) | 73.23th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.54% (0.01537) | 74.52th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.54% (0.01537) | 72.41th | v2 (v2022.01.01) |
| Feb 4, 2022 | 17.17% (0.17166) | 93.10th | v2 (v2022.01.01) |
| Feb 3, 2022 | 9.45% (0.09448) | 86.95th | v1 |
| Jan 6, 2022 | 9.45% (0.09448) | 86.79th | v1 |
| Jan 5, 2022 | 2.27% (0.02273) | 78.61th | v5 (v2026.06.15) |
| Nov 29, 2021 | 2.27% (0.02273) | 78.28th | v1 |
| Sep 1, 2021 | 2.07% (0.02069) | 77.27th | v1 |
| Apr 14, 2021 | 2.07% (0.02069) | 0.00th | v1 |
References (14)
- http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00029.html vendor-advisoryx_refsource_SUSEMailing ListThird Party Advisory
- http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00032.html vendor-advisoryx_refsource_SUSEMailing ListThird Party Advisory
- https://access.redhat.com/security/cve/CVE-2019-17455 Vendor Advisory
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=942145 x_refsource_MISCExploitIssue TrackingMailing ListThird Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1768463 Issue Tracking
- https://gitlab.com/jas/libntlm/issues/2 x_refsource_MISCExploitThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2020/05/msg00010.html mailing-listx_refsource_MLISTMailing ListThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2021/11/msg00026.html mailing-listx_refsource_MLISTMailing ListThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3BVFO3OVJPMSGIXBKNOCVOJZ3UTGZQF5/ vendor-advisoryx_refsource_FEDORA
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YZ5YWYNOJ5HMCKAHWLTY4MXZQWJJCBI7/ vendor-advisoryx_refsource_FEDORA
- https://nvd.nist.gov/vuln/detail/CVE-2019-17455
- https://people.canonical.com/~ubuntu-security/cve/2019/CVE-2019-17455.html x_refsource_CONFIRMThird Party Advisory
- https://security-tracker.debian.org/tracker/CVE-2019-17455 x_refsource_CONFIRMThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2019-17455
Change history (0)
No recorded changes yet.