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CVE-2019-19977

30
FAUCET Score

CVE-2019-19977 is a critical stack-based buffer over-read vulnerability in libESMTP versions up to 1.0.6, specifically within the ntlm_build_type_2 function. This flaw allows an unauthenticated attacker to remotely execute arbitrary code, compromise data confidentiality and integrity, and cause denial of service due to its high CVSS score of 9.8. Despite its severity, there is no known active exploitation, public exploit code, or significant community discussion surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
<= 1.0.6CPE matchmatch criteria
cpe:2.3:a:libesmtp_project:libesmtp:*:*:*:*:*:*:*:*

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
3.06%
Probability of exploitation in next 30 days
EPSS Percentile
86.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0306 is in the 78th percentile among its peer group of 36,835 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 (10)

github_advisorypatch availablevia nvd_reference
View patch
microsoftpatch availablevia msrc
Product: cbl2 libesmtp 1.0.6-21 on CBL Mariner 2.0Fixed in: 1.0.6-21
microsoftpatch availablevia msrc
Product: azl3 libesmtp 1.0.6-21 on Azure Linux 3.0Fixed in: 1.0.6-21
microsoftpatch availablevia msrc
Product: 17041-16823Fixed in: 1.0.6-21
microsoftpatch availablevia msrc
Product: 17042-16817Fixed in: 1.0.6-21
microsoftpatch availablevia msrc
Product: 17042-17084Fixed in: 1.0.6-21
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 x64Fixed in: 1.0.6-21
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 ARMFixed in: 1.0.6-21
microsoftpatch availablevia msrc
Product: Azure Linux 3.0 x64Fixed in: 1.0.6-21
microsoftpatch availablevia msrc
Product: Azure Linux 3.0 ARMFixed in: 1.0.6-21

Vendor Advisories (3)

microsoft2024-Jun/CVE-2019-19977

CVE-2019-19977

Jun 11, 2024
redhatCVE-2019-19977Moderate

libesmtp: Stack-based buffer over-read in ntlm_build_type_2() in ntlm/ntlmstruct.c

Dec 26, 2019
microsoft2019-Dec/CVE-2019-19977Critical

libESMTP through 1.0.6 mishandles domain copying into a fixed-size buffer in ntlm_build_type_2 in ntlm/ntlmstruct.c as demonstrated by a stack-based buffer over-read.

Dec 10, 2019

References

github.com / jbouse-debian/libesmtp/blob/ca5bd0800ef1da234315da4c59716568eb5e6402/ntlm/ntlmstruct.c
ExploitThird Party Advisory
github.com / Kirin-say/Vulnerabilities/blob/master/Stack_Overflow_in_libesmtp.md
ExploitPatchThird Party Advisory
web.archive.org / web/20190528215510/http://brianstafford.info/libesmtp
Product