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CVE-2019-17455

31
FAUCET Score

CVE-2019-17455 is a critical stack-based buffer over-read vulnerability in Libntlm versions up to 1.5, affecting products from Canonical, Debian, Fedora Project, nongnu, and OpenSUSE. It stems from fixed buffer sizes in NTLM authentication request, challenge, and response handling. With a CVSS score of 9.8, this vulnerability allows unauthenticated attackers to achieve high impact on confidentiality, integrity, and availability over the network with low attack complexity. Despite its severity, there is no known public exploit code (Metasploit, Nuclei, ExploitDB), it is not on the KEV catalog, and it has garnered minimal community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
<= 1.5CPE matchmatch criteria
cpe:2.3:a:nongnu:libntlm:*:*:*:*:*:*:*:*
8.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
9.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
14.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:esm:*:*:*
16.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
3.11%
Probability of exploitation in next 30 days
EPSS Percentile
86.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-23
Model: v2026.06.15
This CVE's current EPSS score of 0.0311 is in the 78th percentile among its peer group of 36,821 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (6)

microsoftpatch availablevia msrc
Product: 17027-16823Fixed in: 1.6-1
microsoftpatch availablevia msrc
Product: cbl2 libntlm 1.6-1 on CBL Mariner 2.0Fixed in: 1.6-1
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 x64Fixed in: 1.6-1
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 ARMFixed in: 1.6-1
redhatno patchvia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: libntlm
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: libntlm

Vendor Advisories (3)

microsoft2022-Jan/CVE-2019-17455

CVE-2019-17455

Jan 11, 2022
microsoft2019-Oct/CVE-2019-17455Critical

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.

Oct 8, 2019
redhatCVE-2019-17455Moderate

libntlm: stack-based buffer overflow in buildSmbNtlmAuthRequest in smbutil.c

Oct 8, 2019

References

lists.opensuse.org / opensuse-security-announce/2020-06/msg00029.html
Mailing ListThird Party Advisory
lists.opensuse.org / opensuse-security-announce/2020-06/msg00032.html
Mailing ListThird Party Advisory
bugs.debian.org / cgi-bin/bugreport.cgi
ExploitIssue TrackingMailing ListThird Party Advisory
gitlab.com / jas/libntlm/issues/2
ExploitThird Party Advisory
lists.debian.org / debian-lts-announce/2020/05/msg00010.html
Mailing ListThird Party Advisory
lists.debian.org / debian-lts-announce/2021/11/msg00026.html
Mailing ListThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/3BVFO3OVJPMSGIXBKNOCVOJZ3UTGZQF5
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/YZ5YWYNOJ5HMCKAHWLTY4MXZQWJJCBI7
people.canonical.com / ~ubuntu-security/cve/2019/CVE-2019-17455.html
Third Party Advisory
security-tracker.debian.org / tracker/CVE-2019-17455
Third Party Advisory