CVE-2021-36369

HIGH

Published Oct 12, 20223y ago · Modified Jun 17, 20262w ago

7.5 CVSS 3.1

High

Published Oct 12, 2022 3y ago

Last Modified Jun 17, 2026 2w ago

Description

An issue was discovered in Dropbear through 2020.81. Due to a non-RFC-compliant check of the available authentication methods in the client-side SSH code, it is 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.

CVSS Details

Base Score

7.5

Exploitability

3.9

Impact

3.6

Vector string

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

Attack Vector Network

Attack Complexity Low

Privileges Required None

User Interaction None

Scope Unchanged

Confidentiality None

Integrity High

Availability None

Threat Intelligence

No active exploitation signals — not in CISA KEV and no EPSS score yet.

Exploit & Patch Status

No Known Exploit

No Patch Available

Weaknesses 1

CWE-287 Improper Authentication Authentication

Affected Products 2

Vendor	Product	Version	Range
dropbear_ssh_project	dropbear_ssh	*	≤2020.81
debian	debian_linux	10.0	any

References 4

github.com https://github.com/mkj/dropbear/pull/128

Third Party Advisory
github.com https://github.com/mkj/dropbear/releases

Release NotesThird Party Advisory
github.com https://github.com/mkj/dropbear/releases/tag/DROPBEAR_2022.82

Release NotesThird Party Advisory
lists.debian.org https://lists.debian.org/debian-lts-announce/2022/11/msg00015.html

Mailing ListThird Party Advisory

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.