NULL pointer dereference in Red Hat libssh
Priority LOW 30CWE-476Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · Low
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-476.
Summary
A flaw was found in libssh versions before 0.8.9 and before 0.9.4 in the way it handled AES-CTR (or DES ciphers if enabled) ciphers. The server or client could crash when the connection hasn't been fully initialized and the system tries to cleanup the ciphers when closing the connection. The biggest threat from this vulnerability is system availability.
Why it matters now
EPSS 0.03142 87th percentileScored 2026-11-07
Fix Fixed Red Hat: 2 advisories
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Red Hat | libssh | libssh versions before 0.8.9; libssh versions before 0.9.4 | — | No fix listed | CNA |
- libssh VendorRed Hat Affected libssh versions before 0.8.9; libssh versions before 0.9.4 Fixed in — No fix listed CNA
CPE configurations NVD · 8
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:libssh:libssh:*:*:*:*:*:*:*:* | 0.8.0 to before 0.8.9; 0.9.0 to before 0.9.4 | Vulnerable | libssh |
| cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:* | 18.04 | Vulnerable | Canonical |
| cpe:2.3:o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:* | 19.10 | Vulnerable | Canonical |
| cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:* | 31 | Vulnerable | Fedoraproject |
| cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* | 32 | Vulnerable | Fedoraproject |
| cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* | 8.0 | Vulnerable | Red Hat |
| cpe:2.3:a:oracle:mysql_workbench:*:*:*:*:*:*:*:* | up to 8.0.21 | Vulnerable | Oracle |
- cpe:2.3:a:libssh:libssh:*:*:*:*:*:*:*:* Versions 0.8.0 to before 0.8.9; 0.9.0 to before 0.9.4 Vulnerable ·libssh
- cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:* Versions 18.04 Vulnerable ·Canonical
- cpe:2.3:o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:* Versions 19.10 Vulnerable ·Canonical
- cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:* Versions 31 Vulnerable ·Fedoraproject
- cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* Versions 32 Vulnerable ·Fedoraproject
- cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Red Hat
- cpe:2.3:a:oracle:mysql_workbench:*:*:*:*:*:*:*:* Versions up to 8.0.21 Vulnerable ·Oracle
Remediation
Red Hat 2 advisories
- RHSA-2020:5218 Released 2020-11-24 · Red Hat rating ModerateRed Hat Virtualization security, bug fix, and enhancement update
- Red Hat Virtualization 4 Hypervisor for RHEL 8 redhat-virtualization-host-4.4.3-20201116.0.el8_3, redhat-virtualization-host-image-update-4.4.3-20201116.0.el8_3
- RHSA-2020:4545 Released 2020-11-04 · Red Hat rating Moderatelibssh security, bug fix, and enhancement update
- Red Hat Enterprise Linux AppStream (v. 8) libssh-devel-0.9.4-2.el8
- Red Hat Enterprise Linux BaseOS (v. 8) libssh-0.9.4-2.el8, libssh-config-0.9.4-2.el8
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2020:4545 |
| Red Hat Enterprise Linux BaseOS (v. 8) | Fixed | RHSA-2020:4545 |
| Red Hat Virtualization 4 Hypervisor for RHEL 8 | Fixed | RHSA-2020:5218 |
Not affected: 4 products
- RHEL 8-based RHEV-H for RHEV 4 (build requirements)
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
Timeline
- 2026-10-02 Threatist record created from CVE-2020-1730
- 2026-10-03 Alias added: GHSA-6rh3-m266-5m77
References
More Red Hat Enterprise Linux vulnerabilities
- TI-2019-08259 Underflow in PHP-FPM can lead to RCE KEVCVSS 3.1CRITICAL 9.8
- TI-2018-10530 Code injection in [UNKNOWN] RichFaces KEVCVSS 3.1CRITICAL 9.8
- TI-2014-05975 GNU Bash through 4.3 bash43-025 processes trailing strings after certain malformed… KEVCVSS 3.1CRITICAL 9.8
- TI-2014-05157 GNU Bash through 4.3 processes trailing strings after function definitions in the values… KEVCVSS 3.1CRITICAL 9.8
- TI-2025-23530 Sudo before 1.9.17p1 allows local users to obtain root access because /etc/nsswitch.conf… KEVCVSS 3.1CRITICAL 9.3
- TI-2021-17490 mod_proxy SSRF KEVCVSS 3.1CRITICAL 9.0
Sources
- CVE-2020-1730 · CVE Program
- CVE-2020-1730 · NVD
- FIRST EPSS
- GHSA-6rh3-m266-5m77 · GitHub Advisory Database · CC BY 4.0
- CVE-2020-1730 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences