CVE-2021-36368

3.7 LOW
Published: March 13, 2022 Modified: May 29, 2026
View on NVD

Description

An issue was discovered in OpenSSH before 8.9. If a client is using public-key authentication with agent forwarding but without -oLogLevel=verbose, and an attacker has silently modified the server to support the None authentication option, then the user cannot determine whether FIDO authentication is going to confirm that the user wishes to connect to that server, or that the user wishes to allow that server to connect to a different server on the user's behalf. NOTE: the vendor's position is "this is not an authentication bypass, since nothing is being bypassed.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://bugzilla.mindrot.org/show_bug.cgi?id=3316
Source: cve@mitre.org
Issue Tracking Third Party Advisory
https://docs.ssh-mitm.at/trivialauth.html
Source: cve@mitre.org
Third Party Advisory
https://github.com/openssh/openssh-portable/pull/258
Source: cve@mitre.org
Patch Third Party Advisory
https://security-tracker.debian.org/tracker/CVE-2021-36368
Source: cve@mitre.org
Third Party Advisory
https://www.openssh.com/security.html
Source: cve@mitre.org
Vendor Advisory
https://bugzilla.mindrot.org/show_bug.cgi?id=3316
Source: af854a3a-2127-422b-91ae-364da2661108
Issue Tracking Third Party Advisory
https://docs.ssh-mitm.at/trivialauth.html
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://github.com/openssh/openssh-portable/pull/258
Source: af854a3a-2127-422b-91ae-364da2661108
Patch Third Party Advisory
https://security-tracker.debian.org/tracker/CVE-2021-36368
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://www.openssh.com/security.html
Source: af854a3a-2127-422b-91ae-364da2661108
Vendor Advisory

10 reference(s) from NVD

Quick Stats

CVSS v3 Score
3.7 / 10.0
EPSS (Exploit Probability)
1.7%
74th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

debian openbsd