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PatchSiren cyber security CVE debrief

CVE-2026-76504 Cisco CVE debrief

A hex encoding vulnerability exists in Cisco Catalyst SD-WAN Manager, posing potential operational impacts. Defenders managing Cisco Catalyst SD-WAN Manager deployments should assess exposure and apply mitigations. This issue requires further investigation to validate affected scope, severity, and vendor guidance. The vulnerability is noted in the CISA Known Exploited Vulnerabilities catalog, indicating potential exploitation risks. Defenders should prioritize verification of exposure and apply mitigations as per vendor instructions.

Vendor
Cisco
Product
Catalyst SD-WAN Manager
CVSS
CRITICAL 9.8
CISA KEV
Listed
Original CVE published
2026-09-30
Original CVE updated
2026-09-30
Advisory published
2026-09-30
Advisory updated
2026-09-30

Who should care

Defenders managing Cisco Catalyst SD-WAN Manager deployments should assess exposure and apply mitigations. This includes Verify exposure of Cisco Catalyst SD-WAN Manager to the internet and Apply mitigations in accordance with Cisco instructions. Ensure compliance with CISA’s BOD 26-04 guidance for managing and mitigating vulnerabilities in critical infrastructure.

Why it matters

Defenders should prioritize verification and mitigation of the hex encoding vulnerability in Cisco Catalyst SD-WAN Manager due to potential exploitation risks.

  • Verify exposure of Cisco Catalyst SD-WAN Manager deployments
  • Apply vendor-provided mitigations to prevent potential exploitation

Technical summary

Cisco Catalyst SD-WAN Manager is vulnerable to a hex encoding issue. This vulnerability poses potential operational impacts, including Verify exposure of Cisco Catalyst SD-WAN Manager deployments and Apply vendor-provided mitigations to prevent potential exploitation. Defenders should prioritize verification of exposure and apply mitigations as per vendor instructions.

Defensive priority

Defenders should prioritize verification of exposure and apply mitigations as per vendor instructions.

Recommended defensive actions

  • Verify exposure of Cisco Catalyst SD-WAN Manager to the internet
  • Apply mitigations in accordance with Cisco instructions
  • Ensure compliance with CISA’s BOD 26-04 guidance

Evidence notes

The vulnerability is noted in the CISA Known Exploited Vulnerabilities catalog, indicating potential exploitation risks. Cisco Catalyst SD-WAN Manager is vulnerable to a hex encoding issue. Defenders managing Cisco Catalyst SD-WAN Manager deployments should assess exposure and apply mitigations. The CISA Known Exploited Vulnerabilities catalog entry provides evidence of potential exploitation risks.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-76504 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-76504

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-76504 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-76504

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

  • CISA Known Exploited Vulnerabilities catalog

    Publisher, destination, and source semantics verified

    URL: https://www.cisa.gov/known-exploited-vulnerabilities-catalog

    Cybersecurity and Infrastructure Security Agency - Official CISA catalog of vulnerabilities known to be exploited in the wild.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.