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Fencer Intel
critical 9.1

CVE-2019-3859 json

An out of bounds read flaw was discovered in libssh2 before 1.8.1 in the _libssh2_packet_require and _libssh2_packet_requirev functions.

published 7y ago modified 26d ago also EUVD-2019-13473

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
6.3%
EPSS 6.3% chance of exploitation in 30 days, percentile 93%
public exploits
0
none known

Summary

An out of bounds read flaw was discovered in libssh2 before 1.8.1 in the _libssh2_packet_require and _libssh2_packet_requirev functions. A remote attacker who compromises a SSH server may be able to cause a Denial of Service or read data in the client memory.

Patch / fix

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.5
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • libssh2 Debian 14, Debian 13, Debian 12 1.8.0-2.1

debian advisories DEBIAN-CVE-2019-3859

  • libssh2 Ubuntu Pro 14.04 LTS 1.4.3-2ubuntu0.2+esm2
  • libssh2 Ubuntu Pro 16.04 LTS 1.5.0-2ubuntu0.1+esm1

ubuntu advisories UBUNTU-CVE-2019-3859

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libssh2_org SLES for SAP 15, SLES 15-LTSS, SLE Module for Basesystem 15 SP2 +3 more 1.9.0-4.13.1
  • libssh2_org SLE Point of Sale 11 SP3 1.2.9-4.2.12.8.1
  • libssh2_org SLES for SAP 12 SP4, SLES for SAP 12 SP3, SLES for SAP 12 SP2 +13 more 1.4.3-20.6.1
  • libssh2_org SLE Module for Basesystem 15 1.8.0-4.6.1
  • libssh2_org SLE Point of Sale 11 SP3 1.2.9-4.2.12.5.1
  • libssh2_org SLES for SAP 12 SP4, SLES for SAP 12 SP3, SLES for SAP 12 SP2 +13 more 1.4.3-20.3.1
  • libssh2_org SLES for SAP 11 SP4, SLES 11 SP4, SLE Software Development Kit 11 SP4 1.4.3-17.3.1
  • libssh2_org SLES 11 SP4-LTSS 1.4.3-17.6.1

suse advisories SUSE-SU-2020:3551-1SUSE-SU-2019:14032-1SUSE-SU-2019:1060-1SUSE-SU-2019:1059-1SUSE-SU-2019:14031-1SUSE-SU-2019:13997-1

  • libssh2_org openSUSE Tumbleweed 1.9.0-3.6
  • libssh2_org openSUSE Leap 15.2 1.9.0-lp152.8.3.1
  • libssh2_org openSUSE Leap 15.1 1.9.0-lp151.6.6.1
  • libssh2_org openSUSE Leap 15.0 1.8.0-lp150.3.6.1
  • libssh2_org openSUSE Leap 15.0 1.8.0-lp150.3.3.1

opensuse advisories openSUSE-SU-2024:10999-1openSUSE-SU-2020:2129-1openSUSE-SU-2020:2126-1openSUSE-SU-2019:1291-1openSUSE-SU-2019:1109-1

  • libssh2 Alpine 3.24, Alpine 3.23, Alpine 3.22 +13 more 1.8.1-r0

alpine advisories ALPINE-CVE-2019-3859

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libssh2 Arch Linux 1.8.1-1

arch linux advisories AVG-926

Is CVE-2019-3859 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2019-3859 updated cvss 5.0

libssh2: Unchecked use of _libssh2_packet_require and _libssh2_packet_requirev resulting in out-of-bounds read

  • Red Hat Enterprise Linux 6 libssh2 Red Hat Enterprise Linux 7 libssh2 Red Hat Enterprise Linux 8 libssh2 Red Hat Virtualization 4 rhvm-appliance, redhat-virtualization-host-image-update
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux 8 Advanced Virtualization libssh2
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-23-348-10 updated cvss 9.1

Siemens SIMATIC S7-1500

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.0, < 3.1.5
    affected: fixed in V3.1.5, mitigation support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
10mo ago

Exploit prediction

6.28% chance of exploitation in the next 30 days, higher than 93% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.0 5.0 CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L
CISA ADP 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
NVD 3.0 9.1 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
NVD 2.0 6.4 AV:N/AC:L/Au:N/C:P/I:N/A:P

Affected products

  • The libssh2 Project libssh2
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.