Cisco Security Advisory
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CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:X/RL:X/RC:X
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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, and Cisco Catalyst SD-WAN Manager, formerly SD-WAN vManage, 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. There are no workarounds that address this vulnerability.
Important: To preserve possible indicators of compromise, customers should issue the request admin-tech command from each of the control components in the SD-WAN deployment before upgrading. After the admin-tech file has been collected, software should be upgraded at the earliest opportunity.
This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-rpa2-v69WY2SW
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Vulnerable Products
This vulnerability affects Cisco Catalyst SD-WAN Controller and Cisco Catalyst SD-WAN Manager, regardless of device configuration.
This vulnerability affects all deployment types, including:
- On-Prem Deployment
- Cisco SD-WAN Cloud-Pro
- Cisco SD-WAN Cloud (Cisco Managed)
- Cisco SD-WAN for Government (FedRAMP)
For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory are known to be affected by these vulnerabilities.
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Cisco Catalyst SD-WAN Controller systems that are exposed to the internet and that have ports exposed to the internet are at risk of exposure to compromise. In some instances, these indicators of compromises may occur during standard operations. Therefore, they must be assessed against normal network posture to identify and avoid false positives.
Customers are encouraged to audit the auth.log file, located at /var/log/auth.log, for entries that are related to Accepted publickey for vmanage-admin from unknown or unauthorized IP addresses, as shown in the following example:
2026-02-10T22:51:36+00:00 vm <auth.info> sshd[804]: Accepted publickey for vmanage-admin from <SYSTEM IP ADDRESS> port [REDACTED PORT] ssh2: RSA SHA256:[REDACTED KEY]
Customers must check the IP address in the auth.log log file against the configured System IPs that are listed in the Cisco Catalyst SD-WAN Manager web UI in the WebUI > Devices > System IP column.
For help determining if a Cisco Catalyst SD-WAN Controller or Cisco Catalyst SD-WAN Manager has been compromised, customers should open a case with the Cisco Technical Assistance Center (TAC). TAC cases should be opened as a Severity 3 with the CVE-ID CVE-2026-20182 in the title. Before opening a new TAC case, customers are encouraged to issue the request admin-tech command from each of the control components in the SD-WAN deployment so that the admin-tech file can be provided to the Cisco TAC for review.
Peering Event Validation Guidance
All control connection peering events that are identified in Cisco Catalyst SD-WAN logs require manual validation to confirm their legitimacy, with a specific focus placed on vmanage peering types. Threat actors who compromise SD-WAN infrastructure often establish unauthorized peer connections that may appear superficially normal but occur at unexpected times, originate from unrecognized IP addresses, or involve device types that are inconsistent with the environment's architecture. A comprehensive review process is essential to distinguish between legitimate network operations and potential indicators of compromise.
Validation Checklist
- Verify the timestamp of each peering event against known maintenance windows, scheduled configuration changes, and normal operational hours for your environment.
- Confirm the public IP address corresponds to infrastructure owned or operated by your organization or authorized partners by cross-referencing against asset inventories and authorized IP ranges.
- Validate that the peer system IP matches documented device assignments within your SD-WAN topology.
- Review the peer type (vmanage, vsmart, vedge, vbond) to ensure it aligns with expected device roles in your deployment.
- Correlate multiple events from the same source IP or system IP to identify patterns of reconnaissance or persistent access attempts.
- Cross-reference event timing with authentication logs, change management records, and user activity to establish whether the connection was initiated by authorized personnel.
Example Log Entry
Jul 26 22:03:33 vSmart-01 VDAEMON_0[2571]: %Viptela-vSmart-VDAEMON_0-5-NTCE-1000001: control-connection-state-change new-state:up peer-type:vmanagepeer-system-ip:1.1.1.10 public-ip:192.168.3.20 public-port:12345 domain-id:1 site-id:1005
In the identified example, the peer-system-ip should be validated as matching the expected IP address schema in-use, the timestamp should be validated as matching any events that might cause a peering event to occur, and the public-ip should be validated as being an expected source for a peering event.
Show Control Connections Guidance
To check the command output for the presence of state:up and no challenge-ack for potential compromise, use the commands show control connections detail or show control connections-history detail. If this information shows up in the command output, open a case with the Cisco TAC for further support.
From the CLI of a Controller or Manager: Use either show control connections detail or show control connections-history detail.
From the CLI of a Validator: Use either show orchestrator connections detail or show orchestrator connections-history detail.Example Output:
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REMOTE-COLOR- default SYSTEM-IP- 2.2.2.2 PEER-PERSONALITY- vmanage
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site-id 562
domain-id 0
protocol dtls
protocol-version DTLS1_2
cipher-name ECDHE-RSA-AES256-GCM-SHA384
private-ip 10.0.0.1
private-port 12346
public-ip 192.168.1.1
public-port 50825
org-name orgname-example
state up [Local Err: NO_ERROR] [Remote Err: NO_ERROR]
uptime 0:00:16:58
hello interval 1000
hello tolerance 12000
peer-session-id 0x00eda0acc5Tx Statistics-
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hello 3423293
connects 0
registers 0
register-replies 0
challenge 1
challenge-response 0
challenge-ack 0 <-- challenge-ack 0
teardown 0
teardown-all 0
vmanage-to-peer 0
register-to-vmanage 1
create-cert-reply 0Rx Statistics-
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hello 3423291
connects 0
registers 0
register-replies 0
challenge 0
challenge-response 1
challenge-ack 0 <-- challenge-ack 0
teardown 0
vmanage-to-peer 1
register-to-vmanage 0
create-cert 0
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There are no workarounds that address this vulnerability.
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Cisco considers any workarounds and mitigations (if applicable) to be temporary solutions until an upgrade to a fixed software release is available. To fully remediate this vulnerability and avoid future exposure as described in this advisory, Cisco strongly recommends that customers upgrade to the fixed software indicated in this advisory.
Fixed Releases
In the following table, the left column lists Cisco software releases. The right column indicates whether a release is affected by the vulnerability that is described in this advisory and the first release that includes the fix for this vulnerability. Customers are advised to upgrade to an appropriate fixed software release as indicated in this section.
Cisco Catalyst SD-WAN Release First Fixed Release Earlier than 20.91 Migrate to a fixed release. 20.9 20.9.9.1 20.10 20.12.7.1 20.111 20.12.7.1 20.12 20.12.5.4
20.12.6.2
20.12.7.120.131 20.15.5.2 20.141 20.15.5.2 20.15 20.15.4.4
20.15.5.220.161 20.18.2.2 20.18 20.18.2.2 26.1 26.1.1.1 1. These releases have reached End of Software Maintenance. Cisco strongly encourages customers to upgrade to a supported release.The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.
Cisco has also addressed this vulnerability in Cisco SD-WAN Cloud (Cisco Managed) Release 20.15.506, which is cloud based. No user action is required. Customers can determine the current remediation status or software version by using the Help function in the service GUI.
Customers who need additional information are advised to contact the Cisco TAC or their contracted maintenance providers.
Additional Information
- To check component and software release compatibility, see the Catalyst SD-WAN Control Component Compatibility Matrix.
- For help planning an upgrade, see the Cisco Catalyst SD-WAN Upgrade Matrix.
- For additional remediation assistance, see Remediate Catalyst SD-WAN Security Advisory - May 2026.
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In May 2026, the Cisco Product Security Incident Response Team (PSIRT) became aware of limited exploitation of this vulnerability. Cisco strongly recommends that customers upgrade to a fixed software release to remediate this vulnerability.
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Cisco would like to thank Stephen Fewer, Senior Principal Security Researcher, and Jonah Burgess, Senior Security Researcher, both of Rapid7, for reporting this vulnerability.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Show LessVersion Description Section Status Date 1.0 Initial public release. — Final 2026-MAY-14
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SOFTWARE DOWNLOADS AND TECHNICAL SUPPORT
The Cisco Support and Downloads page on Cisco.com provides information about licensing and downloads. This page can also display customer device support coverage for customers who use the My Devices tool. Please note that customers may download only software that was procured from Cisco directly or through a Cisco authorized reseller or partner and for which the license is still valid.
Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco Technical Assistance Center (TAC). Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.
When considering software upgrades, customers are advised to regularly consult the advisories for the relevant Cisco products to determine exposure and a complete upgrade solution. In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
LEGAL DISCLAIMER DETAILS
CISCO DOES NOT MAKE ANY EXPRESS OR IMPLIED GUARANTEES OR WARRANTIES OF ANY KIND, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. WITHOUT LIMITING THE GENERALITY OF THE FOREGOING, CISCO DOES NOT GUARANTEE THE ACCURACY OR COMPLETENESS OF THIS INFORMATION. THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.
Copies or summaries of the information contained in this Security Advisory may lack important information or contain factual errors. Customers are advised to visit the Cisco Security Advisories page for the most recent version of this Security Advisory. The Cisco Product Security Incident Response Team (PSIRT) assesses only the affected and fixed release information that is documented in this advisory. See the Cisco Security Vulnerability Policy for more information.