CVEvulnerability

CVE-2026-76504

9.8 CRITICAL Known exploited Published 2026-09-30 Modified 2026-10-03 Official page ↗

CISA Known Exploited Vulnerability

Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability — Cisco Catalyst SD-WAN Manager

Cisco Catalyst SD-WAN Manager contains a hex encoding vulnerability that could allow an unauthenticated, remote attacker to access an affected system with privileges of the admin user due to improper handling of URI encoding in an HTTP request.

Added to KEV
2026-09-30
Remediation due
2026-10-03
Ransomware use
Unknown
Required action
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Notes
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-webauth-xr8beuuU ; ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-76504
Status
Analyzed
Published
2026-09-30
Last modified
2026-10-03
Assigner
[email protected]
CVSS 3.1 ([email protected])
9.8 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weaknesses
CWE-177

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.

Affected configurations

• 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 26.2

Related

Weakness · CWE (1)

  • CWE-177 Improper Handling of URL Encoding (Hex Encoding) weakness

References