CVE-2026-76504: Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability
Affects Cisco Catalyst SD-WAN ManagerSource CISA KEV
Exploited in the wild · KEV due 3 Oct 2026 · 1% EPSS : apply the vendor's fix or mitigations to Cisco Catalyst SD-WAN Manager now.
Data as of 10/24/2026, 22:16:05 UTC
- Exploitation
Actively exploited – in CISA KEV since 09/30/2026
- KEV deadline
- 10/03/2026 US federal agencies must patch by this date; a sensible deadline for everyone else.
- EPSS
- 1.8% chance of exploitation in 30 days – higher than 78% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HWhat to do
CISA 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.
- sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-webauth-xr8beuuU (opens in a new tab)
- cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk (opens in a new tab)
- cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-76504 (opens in a new tab)
Check the firmware or software version for Cisco Catalyst SD-WAN Manager in the device's admin interface against the vendor advisory.
Description
CVE-2026-76504 is a critical vulnerability in Cisco Catalyst SD-WAN Manager involving improper handling of URI hex encoding in HTTP requests. This flaw allows an unauthenticated remote attacker to gain admin-level privileges on the affected system. The vulnerability has a CVSS score of 9.8 and is known to be exploited in the wild. No specific affected versions or patch information are provided in the available data.
Impact
An unauthenticated remote attacker can exploit this vulnerability to gain administrative privileges on the affected Cisco Catalyst SD-WAN Manager system. This can lead to full system compromise, including unauthorized access, data disclosure, modification, and potential disruption of service. The confirmed exploitation in the wild increases the urgency and risk associated with this vulnerability.
Mitigation
Monitor Cisco's security advisories closely. Apply any recommended temporary mitigations from Cisco if published. Limit exposure of the affected system to untrusted networks where possible.
Weaknesses
- CWE-177Improper Handling of URL Encoding (Hex Encoding) (opens in a new tab)
Variant weakness
The product does not properly handle when all or part of an input has been URL encoded.
References
- sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-webauth-xr8beuuU (opens in a new tab)
- cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk (opens in a new tab)
- cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-76504 (opens in a new tab)
- cisa.gov/known-exploited-vulnerabilities-catalog?search=CVE-2026-76504 (opens in a new tab)