CVE intelligence and bounded remediation

CVE-2023-33778 — Draytek Myvigor security vulnerability

Critical CVSS 9.8

Draytek Vigor Routers firmware versions below 3.9.6/4.2.4, Access Points firmware versions below v1.4.0, Switches firmware versions below 2.6.7, and Myvigor firmware versions below 2.3.2 were discovered to use hardcoded encryption keys which allows attackers to bind any affected device to their own account. Attackers are then able to create WCF and DrayDDNS licenses and synchronize them from the website.

Severity
Critical
CVSS
9.8 (3.1)
Published
2023-06-01
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-798

Affected products

  • draytek / myvigor
  • draytek / vigorswitch_pq2200xb_firmware
  • draytek / vigorswitch_pq2121x_firmware
  • draytek / vigorswitch_p2540xs_firmware
  • draytek / vigorswitch_p2280x_firmware
  • draytek / vigorswitch_p2100_firmware

Showing 6 representative product identities from 120 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Authentication bypass and missing authentication

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Check exposure

  • Map every affected endpoint and protocol path, including alternate ports, legacy routes, recovery flows, service accounts, and machine-to-machine access.
  • Confirm which deployments enable the affected authentication mode and whether the interface is reachable from untrusted networks.
  • Review session, token, credential, and proxy trust configuration without attempting account takeover.

Remediate safely

  • Apply the supported fix and centralize fail-closed authentication before protected request handling.
  • Remove default or embedded credentials, rotate affected secrets and sessions, and bind authentication decisions to the intended audience and channel.
  • Add negative tests for alternate routes, malformed or absent credentials, recovery flows, and proxy-derived identity.

Authoritative sources

Complete CVE record and remediation plan

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