CVE-2019-17455

Exp

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.

Published: 2019-10-10 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2019-17455 is rated High Exploit Risk (80.3/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 3.11%). 2 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2019-17455

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2019-17455

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 7.08% 3.11% -3.97%
2 2025-12-28 3.93% 7.08% +3.14%
3 2025-12-27 — 3.93% —

Full EPSS history (21 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2019-17455

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-2019-17455

OS Trackers for CVE-2019-17455

vendor priority summary link
debian not yet assigned CVE-2019-17455 not yet assigned priority: Debian including 1 source packages (libntlm), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2019-17455
redhat medium — https://access.redhat.com/security/cve/CVE-2019-17455
ubuntu medium CVE-2019-17455 medium priority: Ubuntu including 1 source packages (libntlm), 11 status rows across 11 suites (bionic, disco, eoan, focal, groovy, hirsute, impish, jammy, trusty, upstream, xenial): released 5, not-affected 4, ignored 2. https://ubuntu.com/security/CVE-2019-17455

Affected software / configurations for CVE-2019-17455

Vendor Product Version Raw CPE
nongnu libntlm <= 1.5 cpe:2.3:a:nongnu:libntlm:*:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
canonical ubuntu_linux 14.04 cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:esm:*:*:*
canonical ubuntu_linux 16.04 cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 18.04 cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 20.04 cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:*
fedoraproject fedora 32 cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
opensuse backports_sle 15.0 cpe:2.3:a:opensuse:backports_sle:15.0:sp1:*:*:*:*:*:*
opensuse leap 15.1 cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*

References for CVE-2019-17455

URL Tags
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00029.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00032.html Mailing List Third Party Advisory
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=942145 Exploit Issue Tracking Mailing List Third Party Advisory
https://gitlab.com/jas/libntlm/issues/2 Exploit Third Party Advisory
https://lists.debian.org/debian-lts-announce/2020/05/msg00010.html Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/11/msg00026.html Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3BVFO3OVJPMSGIXBKNOCVOJZ3UTGZQF5/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YZ5YWYNOJ5HMCKAHWLTY4MXZQWJJCBI7/
https://people.canonical.com/~ubuntu-security/cve/2019/CVE-2019-17455.html Third Party Advisory
https://security-tracker.debian.org/tracker/CVE-2019-17455 Third Party Advisory
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