CVE-2021-20123
Draytek VigorConnect Path Traversal Vulnerability
DrayTek VigorConnect
A local file inclusion vulnerability exists in Draytek VigorConnect 1.6.0-B3 in the file download functionality of the DownloadFileServlet endpoint. An unauthenticated attacker could leverage this vulnerability to download arbitrary files from the underlying operating system with root privileges.
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 3 September 2024. US federal agencies were required to remediate it by 24 September 2024.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 89.7%, which is higher than 99.8% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Frequently asked questions
Is CVE-2021-20123 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2021-20123.
What does CVE-2021-20123 affect?
CVE-2021-20123 affects DrayTek VigorConnect. A local file inclusion vulnerability exists in Draytek VigorConnect 1.6.0-B3 in the file download functionality of the DownloadFileServlet endpoint. An unauthenticated attacker could leverage this vulnerability to download arbitrary files from the underlying operating system with root privileges.
How severe is CVE-2021-20123?
CVE-2021-20123 is rated HIGH with a CVSS base score of 7.5. EPSS puts the probability of exploitation in the next 30 days at 89.7%, higher than 99.8% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 24 September 2024.
How should organisations respond to CVE-2021-20123?
Apply the vendor patch for DrayTek VigorConnect as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.