Authentication Bypass in Cisco Catalyst SD-WAN Products
CVE-2026-20127

10CRITICAL

Key Information:

Vendor

Cisco
Status
Cisco Catalyst Sd-wan Manager
Vendor
CVE Published:
25 February 2026

Badges

🔥 Trending now🥇 Trended No. 1📈 Trended📈 Score: 4,710👾 Exploit Exists🦅 CISA Reported

What is CVE-2026-20127?

CVE-2026-20127 is a significant vulnerability affecting Cisco's Catalyst SD-WAN products, specifically the Catalyst SD-WAN Controller and Manager. These products are designed to optimize and manage wide area network connections for enterprises, enabling them to streamline their connectivity and application performance. The vulnerability stems from a failure in the peering authentication mechanism, which allows unauthorized remote attackers to bypass standard authentication processes. By exploiting this flaw, attackers can gain administrative privileges and access critical network configuration features through NETCONF, a network management protocol. This unauthorized access could lead to severe disruptions, including the manipulation of the SD-WAN infrastructure, ultimately compromising the integrity and security of an organization’s network.

Potential impact of CVE-2026-20127

  1. Unauthorized Access and Privilege Escalation: Attackers can exploit this vulnerability to gain high-privileged access to the Cisco Catalyst SD-WAN Controller, allowing them to manipulate critical network configurations without authentication.

  2. Network Integrity Compromise: With administrative privileges, an attacker can alter network settings, potentially rerouting traffic, creating backdoors, or introducing malicious configurations that could disrupt operations or facilitate further attacks.

  3. Increased Risk of Data Breaches: The ability to control network configuration could lead to unauthorized access to sensitive data transmitted over the SD-WAN, increasing the risk of data breaches and compliance violations within the organization.

CISA has reported CVE-2026-20127

CISA provides regional cyber and physical services to support security and resilience across the United States. CISA monitor the most dangerious vulnerabilities and have identifed CVE-2026-20127 as being exploited but is not known by the CISA to be used in ransomware campaigns. This is subject to change at pace

The CISA's recommendation is: Please adhere to CISA’s guidelines to assess exposure and mitigate risks associated with Cisco SD-WAN devices as outlines in CISA’s Emergency Directive 26-03 (URL listed below in Notes) and CISA’s “Hunt & Hardening Guidance for Cisco SD-WAN Devices (URL listed below in Notes). Adhere to the applicable BOD 22-01 guidance for cloud services or discontinue use of the product if mitigations are not available.

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Affected Version(s)

Cisco Catalyst SD-WAN Manager 20.1.12

Cisco Catalyst SD-WAN Manager 19.2.1

Cisco Catalyst SD-WAN Manager 18.4.4

References

https://sec.cloudapps.cisco.com/security/center/content/C...

CVSS V3.1

Score:
10
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Changed

Timeline

  • 🥇

    Vulnerability reached the number 1 worldwide trending spot

  • 📈

    Vulnerability started trending

  • 👾

    Exploit known to exist

  • 🦅

    CISA Reported

  • Vulnerability published

  • Vulnerability Reserved

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