CVE-2026-76504CiscoRouters and networkingOctober 2, 2026

Cisco Catalyst SD-WAN Manager API Authentication Bypass Vulnerability

Critical 9.8Actively exploited

Description

A vulnerability in the API session-based authentication management of Cisco Catalyst SD-WAN Manager could allow an unauthenticated, remote attacker to access an affected system with privileges of the admin user. This vulnerability is due to improper handling of URI encoding in an HTTP request, which allows the request to bypass an authentication rule that is intended to restrict access to a specific API endpoint. An attacker could exploit this vulnerability by sending a crafted HTTP request to the API of the affected system. A successful exploit could allow the attacker to bypass authentication and gain access to the API as the admin user. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. Live Protect Shield Cisco has released a Live Protect shield for CVE-2026-76504 to provide temporary security coverage to allow time for software upgrade planning, including preserving any information that customers may require for governance or compliance purposes. This shield offers only temporary partial protection. The only way to remediate this vulnerability is to upgrade to the first fixed software release, as noted in the Fixed Releases section of this advisory. Cisco strongly recommends prioritizing system upgrades and scheduling them as soon as possible to ensure remediation. Before deploying the shield, read the following information: Side Effects/Limitation: If this shield is applied A legitimate user with URI encoding might not be able to login to SDWAN Manager. For more information about Live Protect for Cisco Catalyst SD-WAN, see https://www.cisco.com/c/en/us/td/docs/routers/sdwan/26x-later/network-monitoring/network-monitoring-guide/live-protect-for-cisco-catalyst-sd-wan.html . This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-webauth-xr8beuuU Security Impact Rating: Critical CVE: CVE-2026-76504

What to do

Install the fixed versions listed in the official advisory. If you cannot update right away, apply the workarounds or mitigations it describes and limit access to the affected service.

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Details

Vendor
Cisco
Product
Cisco Catalyst SD-WAN Manager
CVE
CVE-2026-76504
Affected versions
Cisco Catalyst SD-WAN Manager 20.1: 7 versions, from 20.1.1 to 20.1.12
Cisco Catalyst SD-WAN Manager 19.2: 14 versions, from 19.2.0 to 19.2.929
Cisco Catalyst SD-WAN Manager 18.4: 10 versions, from 18.4.0 to 18.4.501_ES
Cisco Catalyst SD-WAN Manager 19.3: 19.3.0
Cisco Catalyst SD-WAN Manager 18.3: 11 versions, from 18.3.0 to 18.3.8
Cisco Catalyst SD-WAN Manager 19.0: 19.0.0; 19.0.1a
Cisco Catalyst SD-WAN Manager 19.1: 19.1.0
Cisco Catalyst SD-WAN Manager 17.2: 7 versions, from 17.2.4 to 17.2.10
Cisco Catalyst SD-WAN Manager 18.2: 18.2.0
Cisco Catalyst SD-WAN Manager 20.3: 56 versions, from 20.3.1 to 20.3.814
Cisco Catalyst SD-WAN Manager 20.4: 20 versions, from 20.4.1 to 20.4.2.3
Cisco Catalyst SD-WAN Manager 20.5: 6 versions, from 20.5.0.1.1 to 20.5.1.2
Cisco Catalyst SD-WAN Manager 20.6: 74 versions, from 20.6.0.18.3 to 20.6.8
Cisco Catalyst SD-WAN Manager 20.7: 5 versions, from 20.7.1EFT2 to 20.7.2
Cisco Catalyst SD-WAN Manager 20.8: 20.8.1
Cisco Catalyst SD-WAN Manager 20.9: 76 versions, from 20.9.1EFT2 to 20.9.10.1.01
Cisco Catalyst SD-WAN Manager 20.10: 4 versions, from 20.10.1 to 20.10.1.2
Cisco Catalyst SD-WAN Manager 20.11: 4 versions, from 20.11.1 to 20.11.1.2
Cisco Catalyst SD-WAN Manager 20.12: 46 versions, from 20.12.1 to 20.12.501
Cisco Catalyst SD-WAN Manager 20.13: 20.13.1_LI_Images; 20.13.1
Cisco Catalyst SD-WAN Manager 20.14: 20.14.1; 20.14.1_LI_Images
Cisco Catalyst SD-WAN Manager 20.15: 32 versions, from 20.15.1_LI_Images to 20.15.6.1.01
Cisco Catalyst SD-WAN Manager 20.16: 20.16.1; 20.16.1_LI_Images
Cisco Catalyst SD-WAN Manager 20.18: 18 versions, from 20.18.1 to 20.18.4.1.01
Cisco Catalyst SD-WAN Manager 26.0: 26.0.1
Cisco Catalyst SD-WAN Manager 26.1: 11 versions, from 26.1.1 to 26.1.2.1.01
Cisco Catalyst SD-WAN Manager 26.2: 26.2.1_LI_Images (from the advisory and NVD; check the exact builds in the official advisory)
CVSS score
9.8
Actively exploited
Yes, listed in the CISA Known Exploited Vulnerabilities catalog
Source
Cisco PSIRT – original advisory
Published
October 2, 2026

The description and the recommended action are quoted from the public advisory (the action is our generic advice); severity, exploitation status and affected versions are compiled automatically from public sources and may contain errors. The vendor's original advisory prevails: check it before taking action. This information is provided without warranty and does not replace a professional assessment.

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