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Report · SecurityWeekAbout CVE-2026-20127Published

Recent Cisco Catalyst SD-WAN Vulnerability Now Widely Exploited

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Authoritative record:CVE-2026-20127· Critical 10.0

Exploited in the wild · KEV due 27 Feb 2026 : apply the vendor's fix or mitigations to Cisco Catalyst SD-WAN Manager now.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score
10.0Critical
How severe the flaw is on the 0–10 CVSS scale.
KEV deadline
 US federal agencies must patch by this date; a sensible deadline for everyone else. Other KEV due dates
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

  1. Disclosed: evidence found.

    CVE published 25 Feb 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Exploited in the wild: evidence found.

    Listed in CISA KEV the same day as disclosure

  4. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

Timeline

  1. CVE ID reserved

    by Cisco Systems, Inc.

    , 140 days before disclosure

  2. CVE published

    on cve.org

    , t = 0

  3. In Threat Radar

    record ingested

    , 6 hours after disclosure

  4. , the same day as disclosure

  5. KEV remediation due

    US federal deadline

    , 2 days after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA KEV (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
CiscoCisco Catalyst SD-WAN ManagerAffected
  • 17.2.4 – 20.18.2_LI_Images
331 affected builds
Fixed in–

AI-suggested

Organizations should immediately conduct a thorough inventory of their Cisco Catalyst SD-WAN deployments to identify potentially vulnerable devices. Until official patches or advisories are released, implement network segmentation and restrict management interface access to trusted IP addresses only. Enable and review detailed logging and monitoring on SD-WAN devices to detect anomalous activities or exploitation attempts. Apply strict access controls and multi-factor authentication for administrative access to SD-WAN management consoles. Employ intrusion detection and prevention systems (IDS/IPS) tuned to detect exploitation patterns related to CVE-2026-20127. Coordinate with Cisco support and subscribe to official security advisories to receive timely updates and patches. Conduct penetration testing and vulnerability assessments focused on SD-WAN infrastructure to identify and remediate weaknesses. Finally, develop and rehearse incident response plans specific to SD-WAN compromise scenarios to minimize impact if exploitation occurs.

Description

WatchTowr reports seeing exploitation attempts for CVE-2026-20127 from numerous unique IP addresses. The post Recent Cisco Catalyst SD-WAN Vulnerability Now Widely Exploited appeared first on SecurityWeek .

References

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