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CVE-2026-20127NewsPublished

Cisco SD-WAN Zero-Day Exploitation Tied to Volt Typhoon’s ‘Silent Train’ Network

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Authoritative record:CVE-2026-20127· Critical 10.0

Exploited in the wild · KEV due 27 Feb 2026 : block it and hunt for it in your logs now.

Data as of 29 Oct 2026, 12:32 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 29 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–

Description

A critical zero-day vulnerability (CVE-2026-20127) in Cisco SD-WAN controllers has been exploited by a sophisticated threat actor linked to the Volt Typhoon 'Silent Train' network. The vulnerability allows remote attackers to bypass authentication and gain administrative access to SD-WAN controllers without credentials. Attackers deployed KeyDrift malware to maintain persistent access and steal encryption keys, targeting organizations in sectors such as defense, aerospace, telecommunications, and critical infrastructure. The campaigns have been ongoing since at least late 2025, affecting entities primarily in the United States, with a focus on regions including Hawaii, California, and Texas.

References

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