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VulnerabilityPublished Updated

CVE-2026-20127: Cisco Catalyst SD-WAN Manager · Improper Authentication

Affects Cisco Catalyst SD-WAN ManagerSource CVE Database V5

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Exploited in the wild · KEV due 27 Feb 2026 · 89% EPSS : apply the vendor's fix or mitigations to Cisco Catalyst SD-WAN Manager now.

Data as of 30 Oct 2026, 06:59 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
EPSS
89.2% chance of exploitation in 30 days – higher than 99% 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: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), GitHub proofs of concept, CISA KEV (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

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 Guidance for Cisco SD-WAN Devices (URL listed below in Notes). Adhere to the applicable BOD 22-01 guidance for cloud services or discontinue use of the product if mitigations are not available.

Affected software

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

Check the firmware or software version for Cisco Catalyst SD-WAN Manager in the device's admin interface against the vendor advisory.

Description

CVE-2026-20127 is a critical vulnerability in Cisco Catalyst SD-WAN Manager and related components that allows unauthenticated remote attackers to bypass authentication and gain administrative privileges. The flaw is due to improper functioning of the peering authentication mechanism. Exploitation enables attackers to log in as a high-privileged internal user and access NETCONF to manipulate network configurations of the SD-WAN fabric.

Reports on CVE-2026-20127

References

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