CVE-2021-36368

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.

Category

3.7
CVSS
Severity: Low
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.37%
Vendor Advisory openssh.com
Affected: n/a n/a
Published at:
Updated at:

References

Link Tags
https://www.openssh.com/security.html vendor advisory
https://github.com/openssh/openssh-portable/pull/258 third party advisory patch
https://bugzilla.mindrot.org/show_bug.cgi?id=3316 third party advisory issue tracking
https://docs.ssh-mitm.at/trivialauth.html third party advisory
https://security-tracker.debian.org/tracker/CVE-2021-36368 third party advisory

Frequently Asked Questions

What is the severity of CVE-2021-36368?
CVE-2021-36368 has been scored as a low severity vulnerability.
How to fix CVE-2021-36368?
To fix CVE-2021-36368, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-36368 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-36368 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
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