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CVE-2020-3125

Cisco Adaptive Security Appliance Software Kerberos Authentication Bypass Vulnerability

8.1 High

A vulnerability in the Kerberos authentication feature of Cisco Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to impersonate the Kerberos key distribution center (KDC) and bypass authentication on an affected device that is configured to perform Kerberos authentication for VPN or local device access. The vulnerability is due to insufficient identity verification of the KDC when a successful authentication response is received. An attacker could exploit this vulnerability by spoofing the KDC server response to the ASA device. This malicious response would not have been authenticated by the KDC. A successful attack could allow an attacker to bypass Kerberos authentication.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Exploit likelihood

2.42%Up 1.9 points since Apr 14, 2021
90%50%10%1%

What each source reports

CVE List Score used 8.1

Cisco Adaptive Security Appliance Software Kerberos Authentication Bypass Vulnerability

A vulnerability in the Kerberos authentication feature of Cisco Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to impersonate the Kerberos key distribution center (KDC) and bypass authentication on an affected device that is configured to perform Kerberos authentication for VPN or local device access. The vulnerability is due to insufficient identity verification of the KDC when a successful authentication response is received. An attacker could exploit this vulnerability by spoofing the KDC server response to the ASA device. This malicious response would not have been authenticated by the KDC. A successful attack could allow an attacker to bypass Kerberos authentication.

Record
CVE-2020-3125
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-287
Updated
2026-11-02
EUVDEUVD-2020-24396 8.1

A vulnerability in the Kerberos authentication feature of Cisco Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to impersonate the Kerberos key distribution center (KDC) and bypass authentication on an affected device that is configured to perform Kerberos authentication for VPN or local device access. The vulnerability is due to insufficient identity verification of the KDC when a successful authentication response is received. An attacker could exploit this vulnerability by spoofing the KDC server response to the ASA device. This malicious response would not have been authenticated by the KDC. A successful attack could allow an attacker to bypass Kerberos authentication.

Record
EUVD-2020-24396
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-03
GitHub AdvisoriesGHSA-9x68-6g6c-vj48 9.8

A vulnerability in the Kerberos authentication feature of Cisco Adaptive Security Appliance (ASA)...

A vulnerability in the Kerberos authentication feature of Cisco Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to impersonate the Kerberos key distribution center (KDC) and bypass authentication on an affected device that is configured to perform Kerberos authentication for VPN or local device access. The vulnerability is due to insufficient identity verification of the KDC when a successful authentication response is received. An attacker could exploit this vulnerability by spoofing the KDC server response to the ASA device. This malicious response would not have been authenticated by the KDC. A successful attack could allow an attacker to bypass Kerberos authentication.

Record
GHSA-9x68-6g6c-vj48
CVSS 3.1
9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-287
Updated
2026-11-02
NVD 9.8

A vulnerability in the Kerberos authentication feature of Cisco Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to impersonate the Kerberos key distribution center (KDC) and bypass authentication on an affected device that is configured to perform Kerberos authentication for VPN or local device access. The vulnerability is due to insufficient identity verification of the KDC when a successful authentication response is received. An attacker could exploit this vulnerability by spoofing the KDC server response to the ASA device. This malicious response would not have been authenticated by the KDC. A successful attack could allow an attacker to bypass Kerberos authentication.

Record
CVE-2020-3125
CVSS 3.1
9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0
6.8 MediumAV:N/AC:M/Au:N/C:P/I:P/A:P
Weakness
CWE-287
Updated
2026-11-02

Affected products

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History

History
RecordedChangedSources
facts
aliases, publishedEUVD
first indexedCVE List, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2020-3125 is a high vulnerability (CVSS 8.1) in Cisco Adaptive Security Appliance Software, published May 6, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.42%, the 84th percentile. No source names a fixed version.

References

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