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PatchSiren cyber security CVE debrief

CVE-2026-20127 Cisco CVE debrief

CVE-2026-20127 is a Cisco Catalyst SD-WAN Controller and Manager authentication bypass vulnerability that CISA added to the Known Exploited Vulnerabilities catalog on 2026-02-25. CISA set a remediation due date of 2026-02-27 and pointed defenders to Emergency Directive 26-03 and Cisco’s hunt-and-hardening guidance, so exposed environments should be treated as time-sensitive.

Vendor
Cisco
Product
Catalyst SD-WAN Controller and Manager
CVSS
CRITICAL 10
CISA KEV
Listed
Original CVE published
2026-02-25
Original CVE updated
2026-02-25
Advisory published
2026-02-25
Advisory updated
2026-02-25

Who should care

Organizations running Cisco Catalyst SD-WAN Controller and Manager, especially network operations, security operations, vulnerability management, and incident response teams responsible for SD-WAN environments.

Technical summary

The supplied public records identify an authentication bypass vulnerability in Cisco Catalyst SD-WAN Controller and Manager. The corpus does not provide affected-version ranges, exploitation mechanics, or additional technical detail beyond the CVE name and CISA KEV entry.

Defensive priority

High priority because the issue is listed in CISA’s Known Exploited Vulnerabilities catalog and has a near-term remediation due date. Treat any reachable Cisco Catalyst SD-WAN Controller and Manager deployment as a prompt exposure-check and mitigation candidate.

Recommended defensive actions

  • Check whether any Cisco Catalyst SD-WAN Controller and Manager instances are deployed in your environment.
  • Assess exposure immediately against CISA Emergency Directive 26-03 and Cisco’s hunt-and-hardening guidance.
  • Apply vendor-recommended mitigations or updates as directed by Cisco and CISA.
  • If mitigations are not available, follow the applicable CISA guidance for cloud services or discontinue use of the product, as referenced in the KEV notes.
  • Prioritize monitoring, hunting, and incident-response validation for any exposed SD-WAN management components.

Evidence notes

All factual statements are drawn from the supplied CISA KEV record and the official links listed in the corpus. The record identifies the vulnerability as an authentication bypass affecting Cisco Catalyst SD-WAN Controller and Manager, with dateAdded 2026-02-25 and dueDate 2026-02-27. No additional technical details or CVSS data were supplied in the corpus.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-20127 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-20127

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

  • CVE-2026-20127 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-20127

    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

  • Source item URL

    Unverified legacy reference

    URL: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

    cisa_kev

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.