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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.”

Sources and references

Verified primary and authoritative sources

  • CVE-2021-20123 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2021-20123

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2021-20123 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2021-20123

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

  • CISA Known Exploited Vulnerabilities catalog

    Publisher, destination, and source semantics verified

    URL: https://www.cisa.gov/known-exploited-vulnerabilities-catalog

    Cybersecurity and Infrastructure Security Agency - Official CISA catalog of vulnerabilities known to be exploited in the wild.

Supplemental references

  • Source item URL

    Unverified legacy reference

    URL: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

    cisa_kev

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.