high Known exploitedREV. 01

CVE-2021-20123DrayTek VigorConnect — second download endpoint reads any file

VigorConnect 1.6.0-B3 carries the same unauthenticated file read on a second download endpoint, which returns files from the underlying system with root rights.

YOUR NEXT MOVE

Upgrade VigorConnect past 1.6.0-B3 now; this is the sibling of another endpoint with the same flaw, so one upgrade should close both.

Read the risk

THE VITAL STATS
CVSS score
7.5/ 10
CVSS v3.1
EPSS probability
90%
Likelihood of exploitation
Attack complexity
Low
Conditions needed to exploit
Known exploited
Yes — CISA KEV
CVE published
2021-10-13
Added to KEV
2024-09-03
Exploit published
Yes
Confidence
high
Kill chain
collection
MITRE ATT&CK
T1083
Severity
high

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Attacker needsNetwork access to the management server; no credentials needed.

Behind the card

3 REFERENCES
Field-level provenanceTRACE THE SOURCES +

Which source supports each field, when it was retrieved, and who extracted it.

FieldsSourceRetrievedExtractorConfidence
cvss, exploitation.attack_complexity, exploitation.exploit_available, references, published_atnvd.nist.gov2026-09-24scrty-crds-pipeline/0.1high
exploitation.known_exploited, exploitation.kev_addedcisa.gov2026-09-24scrty-crds-pipeline/0.1high
epssapi.first.org2026-09-24scrty-crds-pipeline/0.1high
title, summary, severity, remediation, mitre_attack, kill_chain, recommended_action, confidence, tags, exploitation.prerequisitesnvd.nist.gov2026-09-24claude-codehigh

Printing history

THE RECORD
  1. r1Initial base card

First printing. This card has not been reprinted since publication.

crds:cve-2021-20123 · CRDS 0.1 · Issued 2026-09-24