Debian Security Advisory

DLA-3187-1 dropbear -- LTS security update

Date Reported:
14 Nov 2022
Affected Packages:
Security database references:
In Mitre's CVE dictionary: CVE-2021-36369.
More information:

An issue was discovered in Dropbear, a relatively small SSH server and client. Due to a non-RFC-compliant check of the available authentication methods in the client-side SSH code, it was possible for an SSH server to change the login process in its favor. This attack can bypass additional security measures such as FIDO2 tokens or SSH-Askpass. Thus, it allows an attacker to abuse a forwarded agent for logging on to another server unnoticed.

For Debian 10 buster, this problem has been fixed in version 2018.76-5+deb10u2.

We recommend that you upgrade your dropbear packages.

For the detailed security status of dropbear please refer to its security tracker page at:

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: