How severe is CVE-2020-27178?

CVE-2020-27178 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2020-27178 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-27178?

CVE-2020-27178 primarily affects Apereo Central Authentication Service. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-27178?

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

When was CVE-2020-27178 published?

CVE-2020-27178 was published on 2020-10-16 and last updated on 2026-06-17.

CVE-2020-27178

CVE-2020-27178 is a high-severity vulnerability in Apereo Central Authentication Service with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (65th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Apereo Central Authentication Service
Published: 2020-10-16
Last modified: 2026-06-17

Description

Apereo CAS 5.3.x before 5.3.16, 6.x before 6.1.7.2, 6.2.x before 6.2.4, and 6.3.x before 6.3.0-RC4 mishandles secret keys with Google Authenticator for multifactor authentication.

Frequently asked questions

What is CVE-2020-27178?: Apereo CAS 5.3.x before 5.3.16, 6.x before 6.1.7.2, 6.2.x before 6.2.4, and 6.3.x before 6.3.0-RC4 mishandles secret keys with Google Authenticator for multifactor authentication.
How severe is CVE-2020-27178?: CVE-2020-27178 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2020-27178 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-27178?: CVE-2020-27178 primarily affects Apereo Central Authentication Service. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-27178?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-27178 published?: CVE-2020-27178 was published on 2020-10-16 and last updated on 2026-06-17.

References

https://apereo.github.io/2020/10/14/gauthvuln/

Affected products (4)

cpe:2.3:a:apereo:central_authentication_service:*:*:*:*:*:*:*:*
cpe:2.3:a:apereo:central_authentication_service:6.3.0:rc1:*:*:*:*:*:*
cpe:2.3:a:apereo:central_authentication_service:6.3.0:rc2:*:*:*:*:*:*
cpe:2.3:a:apereo:central_authentication_service:6.3.0:rc3:*:*:*:*:*:*

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