CVE-2020-1730

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.

Published: 2020-04-13 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-1730 is rated Low Risk (28.7/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.08%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-1730

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-11-21 0.64% 0.08% -0.56%
2 2025-11-18 0.08% 0.64% +0.56%
3 2025-03-30 — 0.08% —

Full EPSS history (16 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-1730

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 3.9 1.4 [email protected]
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 3.9 1.4 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2020-1730

OS Trackers for CVE-2020-1730

vendor priority summary link
alpine medium CVE-2020-1730: 1 source package rows (libssh); 11 state rows across 9 repos (3.10-main, 3.11-main, 3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 9, open 2. https://security.alpinelinux.org/vuln/CVE-2020-1730
debian not yet assigned CVE-2020-1730 not yet assigned priority: Debian including 1 source packages (libssh), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2020-1730
gentoo low CVE-2020-1730: 1 GLSA(s) (202004-08), 1 atom(s) (net-libs/libssh); latest impact low. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2020-1730
redhat medium — https://access.redhat.com/security/cve/CVE-2020-1730
suse medium CVE-2020-1730 severity moderate: SUSE including 383 source package names (0.1.0:libssh4-0.8.7-10.12.1, 0.1.75:libssh4-0.8.7-10.12.1, …), 597 product×package rows across 209 product lines (Container bci/bci-init, Container bci/dotnet-aspnet, … (209 product lines)): Fixed 410, Known Affected 157, Known Not Affected 30. https://www.suse.com/security/cve/CVE-2020-1730/
ubuntu medium CVE-2020-1730 medium priority: Ubuntu including 1 source packages (libssh), 5 status rows across 5 suites (bionic, eoan, trusty, upstream, xenial): released 3, DNE 1, not-affected 1. https://ubuntu.com/security/CVE-2020-1730

Affected software / configurations for CVE-2020-1730

Vendor Product Version Raw CPE
libssh libssh >= 0.8.0, < 0.8.9 cpe:2.3:a:libssh:libssh:*:*:*:*:*:*:*:*
libssh libssh >= 0.9.0, < 0.9.4 cpe:2.3:a:libssh:libssh:*:*:*:*:*:*:*:*
netapp cloud_backup — cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:*
canonical ubuntu_linux 18.04 cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 19.10 cpe:2.3:o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:*
fedoraproject fedora 31 cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
fedoraproject fedora 32 cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
redhat enterprise_linux 8.0 cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
oracle mysql_workbench <= 8.0.21 cpe:2.3:a:oracle:mysql_workbench:*:*:*:*:*:*:*:*

References for CVE-2020-1730

cvelogic Threat Intelligence