Integer overflow in libssh2
Priority MEDIUM 49CWE-190Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 33 fixed, 2 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-190 and the CVSS impact.
Summary
An integer overflow flaw, which could lead to an out of bounds write, was discovered in libssh2 before 1.8.1 in the way keyboard prompt requests are parsed. A remote attacker who compromises a SSH server may be able to execute code on the client system when a user connects to the server.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.06131 93rd percentileScored 2026-11-07
Fix Partial Red Hat: 6 advisoriesRed Hat: 33 fixed, 2 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| The libssh2 Project | libssh2 | 1.8.1 | — | No fix listed | CNA |
- libssh2 VendorThe libssh2 Project Affected 1.8.1 Fixed in — No fix listed CNA
CPE configurations NVD · 16
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:libssh2:libssh2:*:*:*:*:*:*:*:* | before 1.8.1 | Vulnerable | The libssh2 Project |
| cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:* | 8.0 | Vulnerable | Debian |
| cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* | 9.0 | Vulnerable | Debian |
| cpe:2.3:a:netapp:ontap_select_deploy_administration_utility:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:o:opensuse:leap:15.0:*:*:*:*:*:*:* | 15.0 | Vulnerable | openSUSE |
| cpe:2.3:o:opensuse:leap:42.3:*:*:*:*:*:*:* | 42.3 | Vulnerable | openSUSE |
| cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:advanced_virtualization:*:*:* | 8.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_desktop:7.0:*:*:*:*:*:*:* | 7.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:* | 7.0 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_server_aus:7.6:*:*:*:*:*:*:* | 7.6 | Vulnerable | Red Hat |
- cpe:2.3:a:libssh2:libssh2:*:*:*:*:*:*:*:* Versions before 1.8.1 Vulnerable ·The libssh2 Project
- cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Debian
- cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Debian
- cpe:2.3:a:netapp:ontap_select_deploy_administration_utility:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:o:opensuse:leap:15.0:*:*:*:*:*:*:* Versions 15.0 Vulnerable ·openSUSE
- cpe:2.3:o:opensuse:leap:42.3:*:*:*:*:*:*:* Versions 42.3 Vulnerable ·openSUSE
- cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:advanced_virtualization:*:*:* Versions 8.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_desktop:7.0:*:*:*:*:*:*:* Versions 7.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:* Versions 7.0 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_server_aus:7.6:*:*:*:*:*:*:* Versions 7.6 Vulnerable ·Red Hat
Show 6 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:redhat:enterprise_linux_server_eus:7.6:*:*:*:*:*:*:* | 7.6 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_server_tus:7.6:*:*:*:*:*:*:* | 7.6 | Vulnerable | Red Hat |
| cpe:2.3:o:redhat:enterprise_linux_workstation:7.0:*:*:*:*:*:*:* | 7.0 | Vulnerable | Red Hat |
| cpe:2.3:o:fedoraproject:fedora:28:*:*:*:*:*:*:* | 28 | Vulnerable | Fedoraproject |
| cpe:2.3:a:oracle:peoplesoft_enterprise_peopletools:8.56:*:*:*:*:*:*:* | 8.56 | Vulnerable | Oracle |
| cpe:2.3:a:oracle:peoplesoft_enterprise_peopletools:8.57:*:*:*:*:*:*:* | 8.57 | Vulnerable | Oracle |
- cpe:2.3:o:redhat:enterprise_linux_server_eus:7.6:*:*:*:*:*:*:* Versions 7.6 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_server_tus:7.6:*:*:*:*:*:*:* Versions 7.6 Vulnerable ·Red Hat
- cpe:2.3:o:redhat:enterprise_linux_workstation:7.0:*:*:*:*:*:*:* Versions 7.0 Vulnerable ·Red Hat
- cpe:2.3:o:fedoraproject:fedora:28:*:*:*:*:*:*:* Versions 28 Vulnerable ·Fedoraproject
- cpe:2.3:a:oracle:peoplesoft_enterprise_peopletools:8.56:*:*:*:*:*:*:* Versions 8.56 Vulnerable ·Oracle
- cpe:2.3:a:oracle:peoplesoft_enterprise_peopletools:8.57:*:*:*:*:*:*:* Versions 8.57 Vulnerable ·Oracle
Remediation
Red Hat 6 advisories
- RHSA-2019:2399 Released 2019-08-07 · Red Hat rating Importantlibssh2 security update
- Red Hat Enterprise Linux Server AUS (v. 7.3) libssh2-1.4.3-11.el7_3.1
- Red Hat Enterprise Linux Server E4S (v. 7.3) libssh2-1.4.3-11.el7_3.1
- Red Hat Enterprise Linux Server Optional AUS (v. 7.3) libssh2-devel-1.4.3-11.el7_3.1, libssh2-docs-1.4.3-11.el7_3.1
- Red Hat Enterprise Linux Server Optional E4S (v. 7.3) libssh2-devel-1.4.3-11.el7_3.1, libssh2-docs-1.4.3-11.el7_3.1
- Red Hat Enterprise Linux Server Optional TUS (v. 7.3) libssh2-devel-1.4.3-11.el7_3.1, libssh2-docs-1.4.3-11.el7_3.1
- Red Hat Enterprise Linux Server TUS (v. 7.3) libssh2-1.4.3-11.el7_3.1
- RHSA-2019:1943 Released 2019-07-30 · Red Hat rating Importantlibssh2 security update
- Red Hat Enterprise Linux ComputeNode EUS (v. 7.4) libssh2-1.4.3-11.el7_4.1
- Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.4) libssh2-devel-1.4.3-11.el7_4.1, libssh2-docs-1.4.3-11.el7_4.1
- Red Hat Enterprise Linux Server EUS (v. 7.4) libssh2-1.4.3-11.el7_4.1, libssh2-1.4.3-11.el7_4.1.ppc
- Red Hat Enterprise Linux Server Optional EUS (v. 7.4) libssh2-devel-1.4.3-11.el7_4.1, libssh2-devel-1.4.3-11.el7_4.1.ppc, libssh2-docs-1.4.3-11.el7_4.1
- RHSA-2019:1791 Released 2019-07-16 · Red Hat rating Importantlibssh2 security update
- Red Hat Enterprise Linux ComputeNode EUS (v. 7.5) libssh2-1.4.3-11.el7_5.1
- Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.5) libssh2-devel-1.4.3-11.el7_5.1, libssh2-docs-1.4.3-11.el7_5.1
- Red Hat Enterprise Linux Server EUS (v. 7.5) libssh2-1.4.3-11.el7_5.1, libssh2-1.4.3-11.el7_5.1.ppc
- Red Hat Enterprise Linux Server Optional EUS (v. 7.5) libssh2-devel-1.4.3-11.el7_5.1, libssh2-devel-1.4.3-11.el7_5.1.ppc, libssh2-docs-1.4.3-11.el7_5.1
Show 3 more Red Hat advisories
- RHSA-2019:1652 Released 2019-07-02 · Red Hat rating Importantlibssh2 security update
- Red Hat Enterprise Linux Desktop (v. 6) libssh2-1.4.2-3.el6_10.1
- Red Hat Enterprise Linux Desktop Optional (v. 6) libssh2-devel-1.4.2-3.el6_10.1, libssh2-docs-1.4.2-3.el6_10.1
- Red Hat Enterprise Linux HPC Node (v. 6) libssh2-1.4.2-3.el6_10.1
- Red Hat Enterprise Linux HPC Node Optional (v. 6) libssh2-devel-1.4.2-3.el6_10.1, libssh2-docs-1.4.2-3.el6_10.1
- Red Hat Enterprise Linux Server (v. 6) libssh2-1.4.2-3.el6_10.1, libssh2-1.4.2-3.el6_10.1.ppc
- Red Hat Enterprise Linux Server Optional (v. 6) libssh2-devel-1.4.2-3.el6_10.1, libssh2-devel-1.4.2-3.el6_10.1.ppc, libssh2-docs-1.4.2-3.el6_10.1
- Red Hat Enterprise Linux Workstation (v. 6) libssh2-1.4.2-3.el6_10.1
- Red Hat Enterprise Linux Workstation Optional (v. 6) libssh2-devel-1.4.2-3.el6_10.1, libssh2-docs-1.4.2-3.el6_10.1
- RHSA-2019:1175 Released 2019-05-14 · Red Hat rating Importantvirt:rhel security update
- Red Hat Enterprise Linux AppStream (v. 8) SLOF-20171214-5.gitfa98132.module+el8.0.0+3075+09be6b65.noarch::virt:rhel, SLOF-20171214-5.gitfa98132.module+el8.0.0+3075+09be6b65.src::virt:rhel, hivex-1.3.15-6.module+el8.0.0+3075+09be6b65.aarch64::virt:rhel +47
- RHSA-2019:0679 Released 2019-03-28 · Red Hat rating Importantlibssh2 security update
- Red Hat Enterprise Linux Client (v. 7) libssh2-1.4.3-12.el7_6.2
- Red Hat Enterprise Linux Client Optional (v. 7) libssh2-devel-1.4.3-12.el7_6.2, libssh2-docs-1.4.3-12.el7_6.2
- Red Hat Enterprise Linux ComputeNode (v. 7) libssh2-1.4.3-12.el7_6.2
- Red Hat Enterprise Linux ComputeNode Optional (v. 7) libssh2-devel-1.4.3-12.el7_6.2, libssh2-docs-1.4.3-12.el7_6.2
- Red Hat Enterprise Linux Server (v. 7) libssh2-1.4.3-12.el7_6.2, libssh2-1.4.3-12.el7_6.2.ppc
- Red Hat Enterprise Linux Server Optional (v. 7) libssh2-devel-1.4.3-12.el7_6.2, libssh2-devel-1.4.3-12.el7_6.2.ppc, libssh2-docs-1.4.3-12.el7_6.2
- Red Hat Enterprise Linux Workstation (v. 7) libssh2-1.4.3-12.el7_6.2
- Red Hat Enterprise Linux Workstation Optional (v. 7) libssh2-devel-1.4.3-12.el7_6.2, libssh2-docs-1.4.3-12.el7_6.2
- Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server (v. 7) libssh2-1.4.3-12.el7_6.2
- Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server Optional (v. 7) libssh2-devel-1.4.3-12.el7_6.2, libssh2-docs-1.4.3-12.el7_6.2
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Advisory ·
The libssh2 Project libssh2 — openSUSE-SU-2019:1075
9 records Highest priority Priority MEDIUM 9 MEDIUM
Other records, highest priority first
- TI-2019-02869 Out-of-bounds read in libssh2Priority MEDIUM 54
- TI-2019-02865 Integer overflow in libssh2Priority MEDIUM 52
- TI-2019-02872 Out-of-bounds read in libssh2Priority MEDIUM 50
- Advisory ·
The libssh2 Project libssh2 — openSUSE-SU-2019:1109
9 records Highest priority Priority MEDIUM 9 MEDIUM
Other records, highest priority first
- TI-2019-02869 Out-of-bounds read in libssh2Priority MEDIUM 54
- TI-2019-02865 Integer overflow in libssh2Priority MEDIUM 52
- TI-2019-02872 Out-of-bounds read in libssh2Priority MEDIUM 50
Show 8 more groups
- Advisory ·
The libssh2 Project libssh2 — FEDORA-2019-3348cb4934
9 records Highest priority Priority MEDIUM 9 MEDIUM
Other records, highest priority first
- TI-2019-02869 Out-of-bounds read in libssh2Priority MEDIUM 54
- TI-2019-02865 Integer overflow in libssh2Priority MEDIUM 52
- TI-2019-02872 Out-of-bounds read in libssh2Priority MEDIUM 50
- Advisory ·
The libssh2 Project libssh2 — DSA-4431
9 records Highest priority Priority MEDIUM 9 MEDIUM
Other records, highest priority first
- TI-2019-02869 Out-of-bounds read in libssh2Priority MEDIUM 54
- TI-2019-02865 Integer overflow in libssh2Priority MEDIUM 52
- TI-2019-02872 Out-of-bounds read in libssh2Priority MEDIUM 50
- Advisory ·
The libssh2 Project libssh2 — RHSA-2019:0679
4 records Highest priority Priority MEDIUM 4 MEDIUM
Other records, highest priority first
- TI-2019-02865 Integer overflow in libssh2Priority MEDIUM 52
- TI-2019-02867 Integer overflow in libssh2Priority MEDIUM 49
- TI-2019-02873 Integer overflow in libssh2Priority MEDIUM 46
- Advisory ·
The libssh2 Project libssh2 — RHSA-2019:1175
4 records Highest priority Priority MEDIUM 4 MEDIUM
Other records, highest priority first
- TI-2019-02865 Integer overflow in libssh2Priority MEDIUM 52
- TI-2019-02867 Integer overflow in libssh2Priority MEDIUM 49
- TI-2019-02873 Integer overflow in libssh2Priority MEDIUM 46
- Advisory ·
The libssh2 Project libssh2 — RHSA-2019:1652
4 records Highest priority Priority MEDIUM 4 MEDIUM
Other records, highest priority first
- TI-2019-02865 Integer overflow in libssh2Priority MEDIUM 52
- TI-2019-02867 Integer overflow in libssh2Priority MEDIUM 49
- TI-2019-02873 Integer overflow in libssh2Priority MEDIUM 46
- Advisory ·
The libssh2 Project libssh2 — RHSA-2019:1791
4 records Highest priority Priority MEDIUM 4 MEDIUM
Other records, highest priority first
- TI-2019-02865 Integer overflow in libssh2Priority MEDIUM 52
- TI-2019-02867 Integer overflow in libssh2Priority MEDIUM 49
- TI-2019-02873 Integer overflow in libssh2Priority MEDIUM 46
- Advisory ·
The libssh2 Project libssh2 — RHSA-2019:1943
4 records Highest priority Priority MEDIUM 4 MEDIUM
Other records, highest priority first
- TI-2019-02865 Integer overflow in libssh2Priority MEDIUM 52
- TI-2019-02867 Integer overflow in libssh2Priority MEDIUM 49
- TI-2019-02873 Integer overflow in libssh2Priority MEDIUM 46
- Advisory ·
The libssh2 Project libssh2 — RHSA-2019:2399
4 records Highest priority Priority MEDIUM 4 MEDIUM
Other records, highest priority first
- TI-2019-02865 Integer overflow in libssh2Priority MEDIUM 52
- TI-2019-02867 Integer overflow in libssh2Priority MEDIUM 49
- TI-2019-02873 Integer overflow in libssh2Priority MEDIUM 46
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 8 Advanced Virtualization | Affected | No fix yet |
| Red Hat Virtualization 4 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2019:1175 |
| Red Hat Enterprise Linux Client (v. 7) | Fixed | RHSA-2019:0679 |
| Red Hat Enterprise Linux Client Optional (v. 7) | Fixed | RHSA-2019:0679 |
| Red Hat Enterprise Linux ComputeNode (v. 7) | Fixed | RHSA-2019:0679 |
| Red Hat Enterprise Linux ComputeNode EUS (v. 7.4) | Fixed | RHSA-2019:1943 |
| Red Hat Enterprise Linux ComputeNode EUS (v. 7.5) | Fixed | RHSA-2019:1791 |
| Red Hat Enterprise Linux ComputeNode Optional (v. 7) | Fixed | RHSA-2019:0679 |
| Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.4) | Fixed | RHSA-2019:1943 |
| Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.5) | Fixed | RHSA-2019:1791 |
| Red Hat Enterprise Linux Desktop (v. 6) | Fixed | RHSA-2019:1652 |
| Red Hat Enterprise Linux Desktop Optional (v. 6) | Fixed | RHSA-2019:1652 |
| Red Hat Enterprise Linux HPC Node (v. 6) | Fixed | RHSA-2019:1652 |
| Red Hat Enterprise Linux HPC Node Optional (v. 6) | Fixed | RHSA-2019:1652 |
| Red Hat Enterprise Linux Server (v. 6) | Fixed | RHSA-2019:1652 |
| Red Hat Enterprise Linux Server (v. 7) | Fixed | RHSA-2019:0679 |
| Red Hat Enterprise Linux Server AUS (v. 7.3) | Fixed | RHSA-2019:2399 |
| Red Hat Enterprise Linux Server E4S (v. 7.3) | Fixed | RHSA-2019:2399 |
| Red Hat Enterprise Linux Server EUS (v. 7.4) | Fixed | RHSA-2019:1943 |
| Red Hat Enterprise Linux Server EUS (v. 7.5) | Fixed | RHSA-2019:1791 |
| Red Hat Enterprise Linux Server Optional (v. 6) | Fixed | RHSA-2019:1652 |
| Red Hat Enterprise Linux Server Optional (v. 7) | Fixed | RHSA-2019:0679 |
| Red Hat Enterprise Linux Server Optional AUS (v. 7.3) | Fixed | RHSA-2019:2399 |
| Red Hat Enterprise Linux Server Optional E4S (v. 7.3) | Fixed | RHSA-2019:2399 |
| Red Hat Enterprise Linux Server Optional EUS (v. 7.4) | Fixed | RHSA-2019:1943 |
| Red Hat Enterprise Linux Server Optional EUS (v. 7.5) | Fixed | RHSA-2019:1791 |
| Red Hat Enterprise Linux Server Optional TUS (v. 7.3) | Fixed | RHSA-2019:2399 |
| Red Hat Enterprise Linux Server TUS (v. 7.3) | Fixed | RHSA-2019:2399 |
| Red Hat Enterprise Linux Workstation (v. 6) | Fixed | RHSA-2019:1652 |
| Red Hat Enterprise Linux Workstation (v. 7) | Fixed | RHSA-2019:0679 |
| Red Hat Enterprise Linux Workstation Optional (v. 6) | Fixed | RHSA-2019:1652 |
| Red Hat Enterprise Linux Workstation Optional (v. 7) | Fixed | RHSA-2019:0679 |
| Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server (v. 7) | Fixed | RHSA-2019:0679 |
| Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server Optional (v. 7) | Fixed | RHSA-2019:0679 |
Timeline
- 2026-10-02 Threatist record created from CVE-2019-3856
- 2026-10-03 Alias added: GHSA-w4mw-p8mf-732j
References
Patch 3
Advisory 13
- [debian-lts-announce] 20190326 [SECURITY] [DLA 1730-1] libssh2 security update
- https://security.netapp.com/advisory/ntap-20190327-0005/
- RHSA-2019:0679
- openSUSE-SU-2019:1075
- openSUSE-SU-2019:1109
- FEDORA-2019-3348cb4934
- DSA-4431
- 20190415 [SECURITY] [DSA 4431-1] libssh2 security update
- RHSA-2019:1175
- RHSA-2019:1652
- RHSA-2019:1791
- RHSA-2019:1943
- RHSA-2019:2399
More The libssh2 Project Libssh2 vulnerabilities
- TI-2026-39880 libssh2 - Out-of-Bounds Write via Unchecked packet_length in transport.c CVSS 4.0CRITICAL 9.2
- TI-2026-06681 libssh2 userauth.c userauth_password integer overflow CVSS 4.0MEDIUM 6.9
- TI-2023-26623 The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6… CVSS 3.1MEDIUM 5.9
- TI-2026-41806 libssh2 - Free of Uninitialized Pointer in publickey List Cleanup CVSS 4.0HIGH 8.3
- TI-2019-02869 Out-of-bounds read in libssh2 CVSS 3.1CRITICAL 9.1
- TI-2019-02865 Integer overflow in libssh2 CVSS 3.1HIGH 8.8
Sources
- CVE-2019-3856 · CVE Program
- CVE-2019-3856 · NVD
- FIRST EPSS
- GHSA-w4mw-p8mf-732j · GitHub Advisory Database · CC BY 4.0
- CVE-2019-3856 · Red Hat security data · CC BY 4.0
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