Cyber Resilience

CVE-2021-42911

CriticalPublic PoC

Published: 29 March 2022

Published
29 March 2022
Modified
21 November 2024
KEV Added
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Patch
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CVSS Score v3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0387 88.5th percentile
Risk Priority 22 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-42911 is a critical-severity Use of Externally-Controlled Format String (CWE-134) vulnerability in Draytek Vigor2960 Firmware. Its CVSS base score is 9.8 (Critical).

Operationally, ranked in the top 11.5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

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…

more

malicious user execute arbitrary code.

CWE(s)
CWE-134

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

draytek
vigor2960 firmware
≤ 1.5.1.3
draytek
vigor3900 firmware
≤ 1.5.1.3
draytek
vigor300b firmware
≤ 1.5.1.3

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References