Vulnerability in Draytek Vigor2960

CVE-2021-42911

A Format String vulnerability exists in DrayTek Vigor 2960 <= 1.5.1.3, DrayTek Vigor 3900 <= 1.5.1.3, and DrayTek Vigor 300B <= 1.5.1.3 in the mainfunction.cgi file via a crafted HTTP message containing malformed QUERY STRING, which could let a remote malicious user execute arbitrary code.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.035 (88.8th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 89th percentile — 88.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2021-42911: held from 0.035 to 0.035.

EPSS over last 30 days · oldest: 0.035 · newest: 0.035 · change: 0.000

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2021-42911?
CVE-2021-42911 is a critical-severity vulnerability in Draytek Vigor2960, classified under Use of Externally-Controlled Format String. CVSS score: 9.8/10. Published 2022-03-29.
How severe is CVE-2021-42911?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2021-42911 known to be exploited?
3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.