How severe is CVE-2020-27780?

CVE-2020-27780 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-27780 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (79th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-27780?

CVE-2020-27780 affects Linux-pam. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-27780?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2020-27780 published?

CVE-2020-27780 was published on 2020-12-18 and last updated on 2026-06-17.

CVE-2020-27780

CVE-2020-27780 is a critical-severity vulnerability in Linux-pam with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 10.0
EPSS exploit prediction: 2% (79th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Linux-pam
Published: 2020-12-18
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2020-27780?: 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.
How severe is CVE-2020-27780?: CVE-2020-27780 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-27780 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (79th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-27780?: CVE-2020-27780 affects Linux-pam. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-27780?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-27780 published?: CVE-2020-27780 was published on 2020-12-18 and last updated on 2026-06-17.

References

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

Affected products (1)

cpe:2.3:a:linux-pam:linux-pam:*:*:*:*:*:*:*:*

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