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Fencer Vulns
medium 5.3

CVE-2016-20012 json

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…

published 2021-09-15 5 y ago modified 2026-06-17 4 mo ago also EUVD-2016-3100

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
5.3%
EPSS 5.3% chance of exploitation in 30 days, percentile 92%
public exploits
0
none known

Summary

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

Patch / fix

  • openssh Arch Linux 8.9p1-1

arch linux advisories AVG-2392

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2016-20012 updated cvss 5.9

openssh: Public key information leak

  • Red Hat Enterprise Linux 6 openssh, openssh-ldap, openssh-server, openssh-askpass, openssh-clients, pam_ssh_agent_auth Red Hat Enterprise Linux 7 openssh, openssh-cavs, openssh-ldap, openssh-keycat, openssh-server, openssh-askpass, +3 more Red Hat Enterprise Linux 8 openssh, openssh-cavs, openssh-ldap, openssh-keycat, openssh-server, openssh-askpass, +2 more Red Hat Enterprise Linux 9 openssh, openssh-keycat, openssh-server, openssh-askpass, openssh-clients, pam_ssh_agent_auth
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

5.33% chance of exploitation in the next 30 days, higher than 92% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/openssh/openssh-portable/blob/d0fffc88c8fe90c1815c6f4097bc8cbcabc0f3dd/auth2-pubkey.c#L261-L265 referenced PoC, tagged "exploit" by a source, unverified
  • rushter.com https://rushter.com/blog/public-ssh-keys/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:P/I:N/A:N

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.