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.

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…

EPSS: 0.033 (87.0th percentile) — read the EPSS interpretation.

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.

Affected products

Weakness classification (CWE)

CWE-134 — Use of Externally-Controlled Format String

Public proof-of-concept exploits

References

cve@mitre.org (Exploit, Third Party Advisory, x_refsource_MISC)

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.