CVE-2021-42911
9.8 · CRITICALOverview
CVE-2021-42911 is a critical-severity vulnerability affecting draytek vigor2960_firmware. It was published on March 29, 2022 and has a CVSS 3.1 base score of 9.8 (CRITICAL).
This vulnerability has a CVSS 3.1 base score of 9.8, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
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.
Remediation
Check the references section for vendor advisories and patches from draytek. Update vigor2960_firmware to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| draytek | vigor2960_firmware | 0 | Affected |
| draytek | vigor3900_firmware | 0 | Affected |
| draytek | vigor300b_firmware | 0 | Affected |
Frequently Asked Questions
What is CVE-2021-42911?
CVE-2021-42911 is a critical-severity vulnerability affecting draytek vigor2960_firmware. It was published on March 29, 2022 and has a CVSS 3.1 base score of 9.8 (CRITICAL).
How severe is CVE-2021-42911?
This vulnerability has a CVSS 3.1 base score of 9.8, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2021-42911?
Check the references section for vendor advisories and patches from draytek. Update vigor2960_firmware to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-42911?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-42911 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
AI-driven PR review catches vulnerable dependencies before they ship.
Browser-based exploitation validates findings with real proof-of-concept.
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