CVE-2026-20129
CWE-287Published: February 25, 2026· Updated: Feb 27, 2026
Official Description
A vulnerability in the API user authentication of Cisco Catalyst SD-WAN Manager could allow an unauthenticated, remote attacker to gain access to an affected system as a user who has the netadmin role.
The vulnerability is due to improper authentication for requests that are sent to the API. An attacker could exploit this vulnerability by sending a crafted request to the API of an affected system. A successful exploit could allow the attacker to execute commands with the privileges of the netadmin role.
Note: Cisco Catalyst SD-WAN Manager releases 20.18 and later are not affected by this vulnerability.
Technical Analysis
CVE-2026-20129 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.
From a weakness classification perspective (CWE-287): Authentication bypass vulnerabilities allow attackers to access protected resources without valid credentials.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
All References (1)
Quick Facts
Related CVEs (CWE-287)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-20129 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts