CVE-2026-76504: catalyst sd-wan — Actively Exploited & Fix

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.

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CVSS v3.1 Score

9.8

CRITICAL

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

EPSS — Exploit Prediction

0.0182

Probability of exploitation

0.78%

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: Sep 30, 2026 Remediation due: Oct 3, 2026

Weakness Type (CWE)

CWE-177 CWE-177

Affected Products

Vendor	Product	Versions
cisco	catalyst_sd-wan_manager	< 20.9.10.1
cisco	catalyst_sd-wan_manager	20.12 — 20.12.8.2
cisco	catalyst_sd-wan_manager	20.15 — 20.15.6.1
cisco	catalyst_sd-wan_manager	20.18 — 20.18.4.1
cisco	catalyst_sd-wan_manager	26.1 — 26.1.2.1
cisco	catalyst_sd-wan_manager	All

References

Advisories & Patches

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-webauth-xr8beuuU

Other References

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-76504

Frequently Asked Questions

What is CVE-2026-76504? +

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. It has a CVSS v3.1 base score of 9.8 (CRITICAL). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.

How severe is CVE-2026-76504? +

CVE-2026-76504 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0182, placing it in the 1th percentile for exploitation probability.

What products are affected by CVE-2026-76504? +

CVE-2026-76504 affects products from cisco, specifically: catalyst_sd-wan_manager. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-76504? +

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.

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