CVE-2026-20182

Description

May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and fixed after the was disclosed in February 2026. This new advisory is for a new vulnerability in the control connection handshaking. The 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.

CVSS v3.1 Score

10.0

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

EPSS — Exploit Prediction

0.7732

Probability of exploitation

0.99%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

CISA Known Exploited Vulnerability

This vulnerability is actively exploited in the wild.

Added: May 14, 2026 Remediation due: May 17, 2026

Weakness Type (CWE)

CWE-287 Improper Authentication

Affected Products

Vendor	Product	Versions
cisco	catalyst_sd-wan_manager	< 20.9.9.1
cisco	catalyst_sd-wan_manager	20.10 — 20.12.5.4
cisco	catalyst_sd-wan_manager	20.12.6 — 20.12.6.2
cisco	catalyst_sd-wan_manager	20.13 — 20.15.4.4
cisco	catalyst_sd-wan_manager	20.15.5 — 20.15.5.2
cisco	catalyst_sd-wan_manager	20.16 — 20.18.2.2
cisco	catalyst_sd-wan_manager	26.1 — 26.1.1.1
cisco	catalyst_sd-wan_manager	All
cisco	sd-wan_vsmart_controller	< 20.9.9.1
cisco	sd-wan_vsmart_controller	20.10 — 20.12.5.4
cisco	sd-wan_vsmart_controller	20.12.6 — 20.12.6.2
cisco	sd-wan_vsmart_controller	20.13 — 20.15.4.4
cisco	sd-wan_vsmart_controller	20.15.5 — 20.15.5.2
cisco	sd-wan_vsmart_controller	20.16 — 20.18.2.2
cisco	sd-wan_vsmart_controller	26.1 — 26.1.1.1
cisco	sd-wan_vsmart_controller	All

References

Advisories & Patches

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-rpa2-v69WY2SW

Other References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-rpa-EHchtZk https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20182

Frequently Asked Questions

What is CVE-2026-20182? +

May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and fixed after the was disclosed in February 2026. This new advisory is for a new vulnerability in the control connection handshaking. The 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. It has a CVSS v3.1 base score of 10.0 (CRITICAL). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.

How severe is CVE-2026-20182? +

CVE-2026-20182 has a CVSS v3.1 score of 10.0 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.7732, placing it in the 1th percentile for exploitation probability.

What products are affected by CVE-2026-20182? +

CVE-2026-20182 affects products from cisco, specifically: catalyst_sd-wan_manager, sd-wan_vsmart_controller. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-20182? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-48897

Insufficient state checks lead to a vector that allows to bypass 2FA checks.

CVE-2026-48896

Insufficient state checks lead to a vector that allows to bypass 2FA checks.

CVE-2026-47202

Kavita is a cross platform reading server. Prior to 0.9.0.2, an Improper Token validation flaw permits a remote and unauthenticated …

CVE-2026-7876

IBM Aspera HSTS for CP4I 1.5.1 through 1.5.19

CVE-2026-44720

OpenLearnX is an open-source, decentralized learning and assessment platform. Prior to 2.0.4, a critical authentication vulnerability was identified in OpenLearnX …

CVE-2025-24032

PAM-PKCS#11 is a Linux-PAM login module that allows a X.509 certificate based user login. Prior to version 0.6.13, if cert_policy …