Critical [CVE-2026-20182] Cisco Catalyst SD-WAN Controller Authentication Bypass Vulnerability
This critical-severity Cisco advisory covers CVE-2026-20182 affecting Catalyst SD-WAN Manager, Catalyst SD-WAN Controller.
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Summary
May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and fixed after the Cisco Catalyst SD-WAN Controller Authentication Bypass Vulnerability was disclosed in February 2026. This new advisory is for a new vulnerability in the control connection handshaking.
The Indicators of Compromise section of this advisory includes Show Control Connections guidance to help with system checks.
A vulnerability in the peering authentication in Cisco Catalyst SD-WAN Controller, formerly SD-WAN vSmart, Cisco Catalyst SD-WAN Manager, formerly SD-WAN vManage, and Cisco Catalyst SD-WAN Validator, formerly SD-WAN vBond, 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 the 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.
Cisco has released software updates that address this vulnerability.
CISA Known Exploited Vulnerability
- Listed:
- May 14, 2026 · federal remediation due May 17, 2026
- Required action:
- Please adhere to CISA’s guidelines to assess exposure and mitigate risks associated with Cisco SD-WAN devices as outlined 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.
- Ransomware use:
- Unknown
KEV is a prioritization signal from CISA — remediation detail still comes from the vendor advisory.
- Scope: This vulnerability affects Cisco Catalyst SD-WAN Controller, Cisco Catalyst SD-WAN Manager, and Cisco Catalyst SD-WAN Validator, regardless of system configuration.
- Earlier than 20.91 — Migrate to a fixed release
- Release 20.9 (first fixed: 20.9.9.1)
- Release 20.10 (first fixed: 20.12.7.1)
- Release 20.111 (first fixed: 20.12.7.1)
- Release 20.12 (first fixed: 20.12.5.4)
- Release 20.12.6.2 (first fixed: 20.12.7.1)
- Release 20.131 (first fixed: 20.15.5.2)
- Release 20.141 (first fixed: 20.15.5.2)
- Release 20.15 (first fixed: 20.15.4.4)
- Release 20.15.5.2 (first fixed: 20.161)
- Release 20.18.2.2 (first fixed: 20.18)
- Release 20.18.2.2 (first fixed: 26.1)
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
- 20.9.9.1
- 20.12.7.1
- 20.12.5.4
- 20.15.5.2
- 20.15.4.4
- 20.161
- 20.18
- 26.1
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
Mitigation checklist
- If the logs show indicators of compromise and the system is confirmed to be compromised, applying the software update alone will not resolve the vulnerability.
- There are no workarounds that address this vulnerability.
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
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