Type Vulnerability
A newly identified APT group, UAT-11473, was observed exploiting CVE-2026-20127, an authentication-bypass flaw in Cisco Catalyst SD-WAN Controller and Manager. Known-exploited catalogue reports exploitation in the wild.
Cisco · Auth bypass
Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability
CVE-2026-76504
What this means
This is rated critical severity (9.8 out of 10). It is on the known-exploited catalogue, which means attacks using it have already been seen. Ask IT whether Cisco Catalyst Sd Wan Manager is in your estate, and treat that as the priority.
Full vendor 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.
Scoring and exploitation
9.8/ 10
CVSS 3.1 base scoreCritical
Exploitable over the network without any account, and no one has to click or open anything. High impact on confidentiality, integrity and availability.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploitability
Longer bar: easier to attack
Attack vectorNetworkAV:N
Attack complexityLowAC:L
Privileges requiredNonePR:N
User interactionNoneUI:N
ScopeUnchangedS:U
Impact
Longer bar: more harm
ConfidentialityHighC:H
IntegrityHighI:H
AvailabilityHighA:H
- Elevated attack likelihood (~38.9% in 30 days)Model estimate (): a probability signal, not confirmed exploitation
- Exploited in the wild
- Yes — confirmed exploitation (US CISA )
- Not reported
- Listed product
- Cisco Catalyst SD-WAN Manager
Weaknesses
CWE-177
Affected products ()
- Cisco Catalyst Sd Wan Manager
Show the raw CPE strings (2)
- cpe:2.3:a:cisco:catalyst_sd-wan_manager:*:*:*:*:*:*:*:*
- cpe:2.3:a:cisco:catalyst_sd-wan_manager:26.2:*:*:*:*:*:*:*
References
2 links from the CVE record, grouped by site; the vendor's advisory comes first.
sec.cloudapps.cisco.com1 linkVendor advisory
- cisco-sa-sdwan-webauth-xr8beuuU (opens in a new tab)Mitigation · Vendor Advisory
cisa.gov1 link
- known-exploited-vulnerabilities-catalog (opens in a new tab)US Government Resource