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
- Unknown
- 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.
Official resources
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CVE-2026-20127 CVE record
CVE.org
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CVE-2026-20127 NVD detail
NVD
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CISA Known Exploited Vulnerabilities catalog
CISA - Please adhere to CISA’s guidelines to assess exposure and mitigate risks associated with Cisco SD-WAN devices as outlines in CISA’s Emergency Directive 26-03 (URL listed below in Notes) and CISA’s “Hunt & Hardening Guida
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Source item URL
cisa_kev
Public disclosure date in the supplied CVE record and KEV source is 2026-02-25. The provided corpus does not include exploit details, affected-version scope, or CVSS scoring.