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PatchSiren cyber security CVE debrief

CVE-2021-20123 DrayTek CVE debrief

CVE-2021-20123 is a path traversal vulnerability affecting DrayTek VigorConnect. CISA added it to the Known Exploited Vulnerabilities catalog on 2024-09-03, which means defenders should treat it as an active priority and follow vendor remediation guidance promptly. If mitigations are not available, CISA’s catalog entry says to discontinue use of the product.

Vendor
DrayTek
Product
VigorConnect
CVSS
Unknown
CISA KEV
Listed
Original CVE published
2024-09-03
Original CVE updated
2024-09-03
Advisory published
2024-09-03
Advisory updated
2024-09-03

Who should care

Organizations running DrayTek VigorConnect, especially security operations teams, IT administrators, and asset owners responsible for internet-facing or broadly accessible management services.

Technical summary

The published record identifies CVE-2021-20123 as a path traversal issue in DrayTek VigorConnect. The CISA KEV entry lists the vulnerability as known exploited and references the vendor’s security advisory for mitigation guidance. No additional technical details were provided in the supplied corpus.

Defensive priority

High — the vulnerability is listed in CISA’s Known Exploited Vulnerabilities catalog, so it should be prioritized for immediate mitigation or removal.

Recommended defensive actions

  • Review DrayTek’s official security advisory for VigorConnect and follow the vendor’s mitigation instructions.
  • Apply vendor-provided mitigations or updates as soon as they are available.
  • If mitigations are unavailable, discontinue use of VigorConnect as CISA recommends.
  • Inventory all VigorConnect deployments to confirm where the product is in use and whether any instance is exposed.
  • Restrict access and reduce exposure until remediation is complete, especially for externally reachable systems.
  • Monitor official vendor, CISA, and NVD updates for any changes to remediation guidance or product status.

Evidence notes

The supplied corpus identifies the vulnerability as “Draytek VigorConnect Path Traversal Vulnerability,” ties it to vendor DrayTek and product VigorConnect, and records CISA KEV dateAdded 2024-09-03 with dueDate 2024-09-24. The KEV notes point to DrayTek’s official security advisory and the NVD record, and state: “Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.”

Official resources

Use the official CVE and vendor/CISA links for validation. This debrief is based only on the supplied source corpus and does not add unsupported exploit or product details.