CVE-2020-27780

pam: authentication bypass when the user doesn't exist and root password is blank

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Severity

Moderate

Red Hat Product Security

8.1

CVSS 3.1

Review impact separately from score.

Published · October 27, 2020

Updated · November 22, 2025

Description

A flaw was found in Linux-PAM in the way it handles empty passwords for non-existing users. When the user doesn't exist, PAM tries to authenticate with root and with an empty password, authentication is successful. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation

No mitigation is specified in collected source.

CVSS / CWE

CVSS 3.1 · 8.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE-287 · Improper Authentication