How severe is CVE-2020-3125?

CVE-2020-3125 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-2020-3125 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-3125?

CVE-2020-3125 primarily affects Cisco Asa 5505 Firmware. In total, 13 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-3125?

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-2020-3125 published?

CVE-2020-3125 was published on 2020-05-06 and last updated on 2026-06-17.

CVE-2020-3125

CVE-2020-3125 is a critical-severity vulnerability in Cisco Asa 5505 Firmware 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: 6.8
EPSS exploit prediction: 2% (82nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Cisco Asa 5505 Firmware
Published: 2020-05-06
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2020-3125?: 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.
How severe is CVE-2020-3125?: CVE-2020-3125 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-2020-3125 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-3125?: CVE-2020-3125 primarily affects Cisco Asa 5505 Firmware. In total, 13 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-3125?: 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-2020-3125 published?: CVE-2020-3125 was published on 2020-05-06 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-asa-kerberos-bypass-96Gghe2sS

Affected products (13)

cpe:2.3:o:cisco:asa_5505_firmware:9.10\(1.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5510_firmware:9.10\(1.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5512-x_firmware:9.10\(1.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5515-x_firmware:9.10\(1.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5520_firmware:9.10\(1.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5525-x_firmware:9.10\(1.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5540_firmware:9.10\(1.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5545-x_firmware:9.10\(1.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5550_firmware:9.10\(1.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5555-x_firmware:9.10\(1.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5580_firmware:9.10\(1.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:asa_5585-x_firmware:9.10\(1.220\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*

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