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CVE-2019-3855

34
FAUCET Score

CVE-2019-3855 is an integer overflow vulnerability in libssh2 versions prior to 1.8.1, affecting products like Apple, Debian, and Red Hat. This flaw allows a remote attacker, after compromising an SSH server, to potentially execute arbitrary code on a client system when a user connects. With a CVSS score of 8.8 (High), it presents a significant risk due to its network attack vector, low attack complexity, and high impact on confidentiality, integrity, and availability. While no public exploit code or active exploitation has been observed, the vulnerability has garnered some community discussion and media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
< 1.8.1CPE matchmatch criteria
cpe:2.3:a:libssh2:libssh2:*:*:*:*:*:*:*:*
28CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:28:*:*:*:*:*:*:*
29CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:29:*:*:*:*:*:*:*
30CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:*
8.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

7.5HIGH

CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.6
Impact Score
5.9
CvssVersion
3.0

Exploit Intelligence

EPSS Score
9.22%
Probability of exploitation in next 30 days
EPSS Percentile
94.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0922 is in the 95th percentile among its peer group of 14,855 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.2 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.1 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (13)

oraclepatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: libssh2-0:1.4.2-3.el6_10.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: libssh2-0:1.4.3-12.el7_6.2
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.3 Advanced Update SupportFixed in: libssh2-0:1.4.3-11.el7_3.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.3 Telco Extended Update SupportFixed in: libssh2-0:1.4.3-11.el7_3.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.3 Update Services for SAP SolutionsFixed in: libssh2-0:1.4.3-11.el7_3.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.4 Extended Update SupportFixed in: libssh2-0:1.4.3-11.el7_4.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.5 Extended Update SupportFixed in: libssh2-0:1.4.3-11.el7_5.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: virt:rhel-8000020190510171727.55190bc5
View patch
redhatpatch availablevia nvd_reference
View patch
redhatno patchvia redhat_api
Product: Red Hat Enterprise Linux 8 Advanced VirtualizationFixed in: virt:8.0.0/libssh2
redhatend of lifevia redhat_api
Product: Red Hat Virtualization 4Fixed in: redhat-virtualization-host
redhatend of lifevia redhat_api
Product: Red Hat Virtualization 4Fixed in: rhvm-appliance

Vendor Advisories (1)

redhatCVE-2019-3855Important

libssh2: Integer overflow in transport read resulting in out of bounds write

Mar 13, 2019

References

lists.opensuse.org / opensuse-security-announce/2019-03/msg00040.html
Mailing ListThird Party Advisory
lists.opensuse.org / opensuse-security-announce/2019-04/msg00003.html
Third Party Advisory
packetstormsecurity.com / files/152136/Slackware-Security-Advisory-libssh2-Updates.html
Third Party AdvisoryVDB Entry
access.redhat.com / errata/RHSA-2019:0679
Third Party Advisory
access.redhat.com / errata/RHSA-2019:1175
Third Party Advisory
access.redhat.com / errata/RHSA-2019:1652
Third Party Advisory
access.redhat.com / errata/RHSA-2019:1791
Third Party Advisory
access.redhat.com / errata/RHSA-2019:1943
Third Party Advisory
access.redhat.com / errata/RHSA-2019:2399
Third Party Advisory
bugzilla.redhat.com / show_bug.cgi
Issue TrackingPatchThird Party Advisory
seclists.org / fulldisclosure/2019/Sep/42
Mailing ListThird Party Advisory
lists.debian.org / debian-lts-announce/2019/03/msg00032.html
Mailing ListThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/5DK6VO2CEUTAJFYIKWNZKEKYMYR3NO2O
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/6LUNHPW64IGCASZ4JQ2J5KDXNZN53DWW
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/M7IF3LNHOA75O4WZWIHJLIRMA5LJUED3
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/XCWEA5ZCLKRDUK62QVVYMFWLWKOPX3LO
seclists.org / bugtraq/2019/Apr/25
Mailing ListThird Party Advisory
seclists.org / bugtraq/2019/Mar/25
Mailing ListThird Party Advisory
seclists.org / bugtraq/2019/Sep/49
Mailing ListThird Party Advisory
security.netapp.com / advisory/ntap-20190327-0005
Third Party Advisory
support.apple.com / kb/HT210609
Third Party Advisory
broadcom.com / support/fibre-channel-networking/security-advisories/brocade-security-advisory-2019-767
Third Party Advisory
debian.org / security/2019/dsa-4431
Third Party Advisory
libssh2.org / CVE-2019-3855.html
PatchVendor Advisory
oracle.com / technetwork/security-advisory/cpuoct2019-5072832.html
PatchThird Party Advisory
openwall.com / lists/oss-security/2019/03/18/3
Mailing ListPatchThird Party Advisory
securityfocus.com / bid/107485
Third Party AdvisoryVDB Entry