CVE-2021-1614: Cisco SD-WAN Software Information Disclosure Vulnerability

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-07-22 · updated 2026-06-17
Weakness: CWE-126

Description

A vulnerability in the Multiprotocol Label Switching (MPLS) packet handling function of Cisco SD-WAN Software could allow an unauthenticated, remote attacker to gain access to information stored in MPLS buffer memory. This vulnerability is due to insufficient handling of malformed MPLS packets that are processed by a device that is running Cisco SD-WAN Software. An attacker could exploit this vulnerability by sending a crafted MPLS packet to an affected device that is running Cisco SD-WAN Software or Cisco SD-WAN vManage Software. A successful exploit could allow the attacker to gain unauthorized access to sensitive information.

Affected products

Cisco Sd-Wan: from 18.4.0 before 18.4.6; from 19.2.0 before 19.2.3; from 20.3 before 20.3.2; from 20.4 before 20.4.1; from 20.5 before 20.5.1 — fixed in 18.4.6, 19.2.3, 20.3.2, 20.4.1, 20.5.1

How to fix

Upgrade to a fixed version: Cisco Sd-Wan 18.4.6, 19.2.3, 20.3.2, 20.4.1. Check the vendor advisory for mitigations.

References

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