CVE-2026-20127 Cisco Catalyst SD-WAN Controller and Manager: login or permission bypass
In plain words: A door that should be locked is not: part of the system can be reached without a valid login or permission. The attacker gets in as a user or administrator without knowing a password.
Confirmed exploited by CISA on · US federal patch deadline Feb 27, 2026
What to do
- Install Cisco's security update for Catalyst SD-WAN Controller and Manager. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Patch edge devices first — attackers often start scanning for them within hours of a fix.
- Never expose the device's admin page to the internet.
- After patching a device that was exposed, follow the vendor's compromise checks, end active sessions and change passwords.
Who is affected
Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.
What's at risk: They face the internet and guard the whole network, so a flaw here can hand attackers a way in — and these devices usually run no antivirus, so break-ins go unnoticed.
The details
- Official name
- Cisco Catalyst SD-WAN Controller and Manager Authentication Bypass Vulnerability
- Product
- Cisco Catalyst SD-WAN Controller and Manager
- CISA description
- Cisco Catalyst SD-WAN Controller, formerly SD-WAN vSmart, and Cisco Catalyst SD-WAN Manager, formerly SD-WAN vManage, contain an authentication bypass vulnerability could allow an unauthenticated, remote attacker to bypass authentication and obtain administrative privileges on an affected system. This vulnerability exists because the peering authentication mechanism in an affected system is not working properly. An attacker could exploit this vulnerability by sending crafted requests to an affected system. A successful exploit could allow the attacker to log in to an affected Cisco Catalyst SD-WAN Controller as an internal, high-privileged, non-root user account. Using this account, the attacker could access NETCONF, which would then allow the attacker to manipulate network configuration for the SD-WAN fabric.
- Type of flaw
- Login or permission bypass (CWE-287)
- Confirmed exploited
- Feb 25, 2026
- US federal patch deadline
- Feb 27, 2026
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Answering about CVE-2026-20127 ·
Questions about CVE-2026-20127
Is CVE-2026-20127 being exploited?
Yes. CISA added CVE-2026-20127 to its Known Exploited Vulnerabilities catalog on Feb 25, 2026, which means there is reliable evidence of real-world attacks.
How do I fix CVE-2026-20127?
Install Cisco's security update for Catalyst SD-WAN Controller and Manager. If no update exists, follow the vendor's workaround or stop using the product until one ships. Patch edge devices first — attackers often start scanning for them within hours of a fix.
Am I affected by CVE-2026-20127?
Only if you use Cisco Catalyst SD-WAN Controller and Manager. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.