Secuno
ENNL
Book demo

CVE-2026-76504

Cisco Catalyst SD-WAN Manager Hex Encoding

9.8 CRITICALActively exploited (CISA KEV)EPSS 1.82%
  1. Published30 Sept 2026
  2. Added to CISA KEV30 Sept 2026
  3. Remediation due3 Oct 2026
Actively exploited (CISA KEV)

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: 30 Sept 2026Federal remediation due: 3 Oct 2026

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Cisco Catalyst SD-WAN Manager≥ 20.12 < 20.12.8.2 · ≥ 20.15 < 20.15.6.1 · ≥ 20.18 < 20.18.4.1 · ≥ 26.1 < 26.1.2.1

Remediation

Fixed in
Cisco Catalyst SD-WAN Manager≥ 20.12.8.2

References

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

CVE-2026-153718.1
Velociraptor's web GUI allows specifying a custom type for columns in tables. The URL…
CVE-2026-590839.1
Improper Handling of URL Encoding (Hex Encoding) vulnerability in Apache Tomcat's…
CVE-2026-410419.1
URL path injection via unencoded user-supplied identifiers vulnerability in Apache…
CVE-2026-220378.4
The @fastify/express plugin adds full Express compatibility to Fastify. A security…
CVE-2026-220318.4
@fastify/middie is the plugin that adds middleware support on steroids to Fastify. A…

Frequently asked

Is CVE-2026-76504 being actively exploited?

Yes. CVE-2026-76504 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 30 Sept 2026.

How severe is CVE-2026-76504?

CVE-2026-76504 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 1.82% probability of exploitation.

Which products are affected by CVE-2026-76504?

Affected products include Cisco Catalyst SD-WAN Manager.

How do I fix CVE-2026-76504?

Upgrade affected software to a fixed version, for example Cisco Catalyst SD-WAN Manager 20.12.8.2 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-76504 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, Secuno flags any affected asset as top-priority automatically. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

See how prioritisation worksBook a demo

Get Patch this first every Monday

Five vulnerabilities that matter this week, ranked on real exploitation. Plain language, one email, no spam.

You can unsubscribe with one click from every issue. We handle your details as described in our privacy policy.

Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.