CVE-2016-20012

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Summary

CVECVE-2016-20012
StatePUBLISHED
Assignermitre
Source PriorityCVE Program / NVD first with legacy fallback
Published2021-09-15 20:15:07 UTC
Updated2026-05-29 16:16:16 UTC
DescriptionOpenSSH 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

Risk And Classification

Primary CVSS: v3.1 5.3 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS: 0.086470000 probability, percentile 0.925900000 (date 2026-06-03)

Problem Types: NVD-CWE-Other | CWE-203 | n/a | CWE-203 CWE-203 Observable Discrepancy

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
3.1ADPDECLARED5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
2.0[email protected]Primary4.3AV:N/AC:M/Au:N/C:P/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS v2.0 Breakdown

Access Vector
Network
Access Complexity
Medium
Authentication
None
Confidentiality
Partial
Integrity
None
Availability
None

AV:N/AC:M/Au:N/C:P/I:N/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Netapp Clustered Data Ontap - All All All
Application Netapp Hci Management Node - All All All
Application Netapp Ontap Select Deploy Administration Utility - All All All
Application Netapp Solidfire - All All All
Application Openbsd Openssh All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Na N/a affected n/a Not specified

References

ReferenceSourceLinkTags
Publickey User Enumeration - Only allow SSH_MSG_USERAUTH_REQUEST with signature by manfred-kaiser · Pull Request #270 · openssh/openssh-portable · GitHub af854a3a-2127-422b-91ae-364da2661108 github.com Patch, Third Party Advisory
CVE-2016-20012 - Publickey Information leak - Only allow SSH_MSG_USERAUTH_REQUEST with signature by manfred-kaiser · Pull Request #270 · openssh/openssh-portable · GitHub af854a3a-2127-422b-91ae-364da2661108 github.com Issue Tracking, Third Party Advisory
oss-security - About OpenSSH "user enumeration" / CVE-2018-15473 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com Mailing List, Third Party Advisory
Chris's Wiki :: blog/tech/SSHKeysAreInfoLeak af854a3a-2127-422b-91ae-364da2661108 utcc.utoronto.ca Third Party Advisory
CVE-2016-20012 - Publickey Information leak - Only allow SSH_MSG_USERAUTH_REQUEST with signature by manfred-kaiser · Pull Request #270 · openssh/openssh-portable · GitHub af854a3a-2127-422b-91ae-364da2661108 github.com Issue Tracking, Third Party Advisory
Public SSH keys can leak your private infrastructure | Artem Golubin af854a3a-2127-422b-91ae-364da2661108 rushter.com Exploit, Third Party Advisory
openssh-portable/auth2-pubkey.c at d0fffc88c8fe90c1815c6f4097bc8cbcabc0f3dd · openssh/openssh-portable · GitHub 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com Exploit, Third Party Advisory
CVE-2016-20012 OpenSSH Vulnerability in NetApp Products | NetApp Product Security af854a3a-2127-422b-91ae-364da2661108 security.netapp.com Third Party Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Legacy QID Mappings

  • 38903 OpenSSH Probable User Enumeration Vulnerability
  • 900458 Common Base Linux Mariner (CBL-Mariner) Security Update for openssh (5921)

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