CVE-2020-3139: Cisco Application Policy Infrastructure Controller Out Of Band Management IP Tables Bypass Vulnerability

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-01-26 · updated 2026-06-17
Weakness: CWE-20

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).

Affected products

Cisco Application Policy Infrastructure Controller (APIC): before 4.2\(3j\) — fixed in 4.2\(3j\)

How to fix

Upgrade to a fixed version: Cisco Application Policy Infrastructure Controller (APIC) 4.2\(3j\). Check the vendor advisory for mitigations.

References

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