CVE-2020-3139: A vulnerability in the out of band (OOB) management interface IP table rule programming for Cisco Application Policy Infrastructure Controller (APIC) ...

Description

A vulnerability in the out of band (OOB) management interface IP table rule programming for Cisco Application Policy Infrastructure Controller (APIC) could allow an unauthenticated, remote attacker to bypass configured deny entries for specific IP ports. These IP ports would be permitted to the OOB management interface when, in fact, the packets should be dropped. The vulnerability is due to the configuration of specific IP table entries for which there is a programming logic error that results in the IP port being permitted. An attacker could exploit this vulnerability by sending traffic to the OOB management interface on the targeted device. A successful exploit could allow the attacker to bypass configured IP table rules to drop specific IP port traffic. The attacker has no control over the configuration of the device itself. This vulnerability affects Cisco APIC releases prior to the first fixed software Release 4.2(3j).

Metrics

CVSS 3.1

5.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS Probability

1.04%

59.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Cisco	Application Policy Infrastructure Controller	< 4.2\(3j\)

References

Timeline

Published: Jan 26, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-3139?

A vulnerability in the out of band (OOB) management interface IP table rule programming for Cisco Application Policy Infrastructure Controller (APIC) could allow an unauthenticated, remote attacker to bypass configured deny entries for specific IP ports. These IP ports would be permitted to the OOB management interface when, in fact, the packets should be dropped. The vulnerability is due to the configuration of specific IP table entries for which there is a programming logic error that results in the IP port being permitted. An attacker could exploit this vulnerability by sending traffic to the OOB management interface on the targeted device. A successful exploit could allow the attacker to bypass configured IP table rules to drop specific IP port traffic. The attacker has no control over the configuration of the device itself. This vulnerability affects Cisco APIC releases prior to the first fixed software Release 4.2(3j).

How severe is CVE-2020-3139?

CVE-2020-3139 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 1.04% probability of exploitation in the next 30 days.

How do I fix CVE-2020-3139?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.