Libntlm through 1.5 relies on a fixed buffer size for tSmbNtlmAuthRequest…
Priority MEDIUM 48CWE-125Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
EPSS 0.03107 87th percentileScored 2026-11-07
Public exploit Yes 2 exploit referencesTagged by NVD
Fix No fix listed No fixed version in the sources yet
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 11
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:nongnu:libntlm:*:*:*:*:*:*:*:* | up to 1.5 | Vulnerable | Nongnu |
| cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:* | 8.0 | Vulnerable | Debian |
| cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* | 9.0 | Vulnerable | Debian |
| cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:esm:*:*:* | 14.04 | Vulnerable | Canonical |
| cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:* | 16.04 | Vulnerable | Canonical |
| cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:* | 18.04 | Vulnerable | Canonical |
| cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:* | 20.04 | Vulnerable | Canonical |
| cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* | 32 | Vulnerable | Fedoraproject |
| cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* | 33 | Vulnerable | Fedoraproject |
| cpe:2.3:a:opensuse:backports_sle:15.0:sp1:*:*:*:*:*:* | 15.0 sp1 | Vulnerable | openSUSE |
- cpe:2.3:a:nongnu:libntlm:*:*:*:*:*:*:*:* Versions up to 1.5 Vulnerable ·Nongnu
- cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Debian
- cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Debian
- cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:esm:*:*:* Versions 14.04 Vulnerable ·Canonical
- cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:* Versions 16.04 Vulnerable ·Canonical
- cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:* Versions 18.04 Vulnerable ·Canonical
- cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:* Versions 20.04 Vulnerable ·Canonical
- cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* Versions 32 Vulnerable ·Fedoraproject
- cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* Versions 33 Vulnerable ·Fedoraproject
- cpe:2.3:a:opensuse:backports_sle:15.0:sp1:*:*:*:*:*:* Versions 15.0 sp1 Vulnerable ·openSUSE
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise Linux 7 | Affected | No fix yet |
| Red Hat Satellite 5 | Affected | No fix planned: Out of support scope |
Timeline
- 2026-10-02 Threatist record created from CVE-2019-17455
- 2026-10-03 Alias added: GHSA-m8c7-4hj3-f3m6
References
Exploit 2
Advisory 8
- https://people.canonical.com/~ubuntu-security/cve/2019/CVE-2019-17455.html
- https://security-tracker.debian.org/tracker/CVE-2019-17455
- [debian-lts-announce] 20200510 [SECURITY] [DLA 2207-1] libntlm security update
- openSUSE-SU-2020:0816
- openSUSE-SU-2020:0806
- FEDORA-2020-8794383d6f
- FEDORA-2020-1f643c272c
- [debian-lts-announce] 20211128 [SECURITY] [DLA 2831-1] libntlm security update
Sources
- CVE-2019-17455 · CVE Program
- CVE-2019-17455 · NVD
- FIRST EPSS
- GHSA-m8c7-4hj3-f3m6 · GitHub Advisory Database · CC BY 4.0
- CVE-2019-17455 · Red Hat security data · CC BY 4.0
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