CVE-2026-76504KEV · OVERDUECWE-177

Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability

Critical · published September 30, 2026

Patch now

Confirmed exploited, and the score agrees

CVSS calls it critical at 9.8. It is confirmed in active exploitation. It sits in the 78.6th percentile for exploit probability.

21
days past CISA
deadline
CVSS v3.1
9.8
EPSS
2%
Percentile
78.6
In the wild
Confirmed
What it is

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.

The record
Technical detail
CVSS v3.1
9.8 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.01819 · 78.6th percentile
Weakness
CWE-177 · Improper Handling of URL Encoding (Hex Encoding)
Published
2026-09-30T17:17Z
KEV added
2026-09-30 · due 2026-10-03
Affected products (6)
ProductVersionsFixed in
cisco/catalyst_sd-wan_manager< 20.9.10.120.9.10.1
cisco/catalyst_sd-wan_manager≥ 20.12, < 20.12.8.220.12.8.2
cisco/catalyst_sd-wan_manager≥ 20.15, < 20.15.6.120.15.6.1
cisco/catalyst_sd-wan_manager≥ 20.18, < 20.18.4.120.18.4.1
cisco/catalyst_sd-wan_manager≥ 26.1, < 26.1.2.126.1.2.1
cisco/catalyst_sd-wan_managerall versions—
References (2)
EPSS history
Timeline
  • 02 OCT 03:46Z
    EPSS moved — → 1%
    epss
  • 30 SEP 13:04Z
    Cisco Catalyst SD-WAN Manager System Account Authorization Bypass Vulnerability
    cvelistv5
  • 30 SEP 00:00Z
    Added to CISA KEV — remediate by Oct 3
    kev