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Known exploited vulnerability

CVE-2026-76504

criticalCVSS 3.1 9.8In CISA KEVEPSS 39%Published · Cisco

The short answer

CVE-2026-76504 affects Cisco Cisco Catalyst SD-WAN Manager and is rated critical (CVSS 9.8). CISA added it to the Known Exploited Vulnerabilities catalog on 2026-09-30: attackers are using it, so patch it first.

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.

Weakness: CWE-177.

Severity

9.8 critical

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

Exploited (CISA KEV)

Yes, since Sep 30, 2026

Federal due date Oct 3, 2026

EPSS, next 30 days

39%

Higher than 99% of scored CVEs

How it can be exploited

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

What CISA says to do

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…

Affected products

Cisco Catalyst SD-WAN Manager. NVD's record lists the exact affected versions.

References

Questions

Is CVE-2026-76504 being exploited?

Yes. CISA added CVE-2026-76504 to its Known Exploited Vulnerabilities catalog on 2026-09-30, with a federal remediation due date of 2026-10-03.

How do I fix CVE-2026-76504?

CISA's 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…

From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.

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