CVE-2020-27780

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-12-18 · updated 2026-06-17
Weakness: CWE-287

Description

A flaw was found in Linux-Pam in versions prior to 1.5.1 in the way it handle empty passwords for non-existing users. When the user doesn't exist PAM try to authenticate with root and in the case of an empty password it successfully authenticate.

Affected products

Linux-PAM: from 1.5.0 before 1.5.1 — fixed in 1.5.1

How to fix

Upgrade to a fixed version: Linux-PAM 1.5.1. Check the vendor advisory for mitigations.

References

https://bugzilla.redhat.com/show_bug.cgi?id=1901094
https://bugzilla.redhat.com/show_bug.cgi?id=1901094

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