CVE-2016-20012

Exp

OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of username and public key is known to an SSH server, to test whether this suspicion is correct. This occurs because a challenge is sent only when that combination could be valid for a login session. NOTE: the vendor does not recognize user enumeration as a vulnerability for this product

Published: 2021-09-15 Last update: 2026-05-29 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2016-20012 is rated High Exploit Risk (64.5/100): CVSS Medium severity, with high exploitation likelihood (EPSS 5.04%, 91th percentile). 2 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

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

Public exploit references (Exploit-DB) for CVE-2016-20012

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2016-20012

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 2026-06-15 8.65% 5.04% -3.61%
2 2026-05-30 14.60% 8.65% -5.96%
3 2026-04-23 — 14.60% —

Full EPSS history (49 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-20012

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:L/I:N/A:N 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:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 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:L/I:N/A:N 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:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 1.4 134c704f-9b21-4f2e-91b3-4a467353bcc0
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2016-20012

GitHub Security Advisory for CVE-2016-20012

GHSA-84j4-ccmw-hwpg · Severity: medium — OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of...

OS Trackers for CVE-2016-20012

vendor priority summary link
alpine — CVE-2016-20012: 1 source package rows (openssh); 30 state rows across 5 repos (3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 0, open 30. https://security.alpinelinux.org/vuln/CVE-2016-20012
debian unimportant CVE-2016-20012 unimportant priority: Debian including 1 source packages (openssh), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 5. https://security-tracker.debian.org/tracker/CVE-2016-20012
redhat low — https://access.redhat.com/security/cve/CVE-2016-20012
suse low — https://www.suse.com/security/cve/CVE-2016-20012/
ubuntu negligible CVE-2016-20012 negligible priority: Ubuntu including 2 source packages (openssh, openssh-ssh1), 16 status rows across 8 suites (bionic, focal, hirsute, impish, jammy, trusty, upstream, xenial): ignored 14, DNE 2. https://ubuntu.com/security/CVE-2016-20012

Affected software / configurations for CVE-2016-20012

Vendor Product Version Raw CPE
openbsd openssh <= 8.7 cpe:2.3:a:openbsd:openssh:*:*:*:*:*:*:*:*
netapp clustered_data_ontap — cpe:2.3:a:netapp:clustered_data_ontap:-:*:*:*:*:*:*:*
netapp hci_management_node — cpe:2.3:a:netapp:hci_management_node:-:*:*:*:*:*:*:*
netapp ontap_select_deploy_administration_utility — cpe:2.3:a:netapp:ontap_select_deploy_administration_utility:-:*:*:*:*:*:*:*
netapp solidfire — cpe:2.3:a:netapp:solidfire:-:*:*:*:*:*:*:*

References for CVE-2016-20012

cvelogic Threat Intelligence