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CVE-2021-42911

CRITICALCVSS 9.8/10EPSS 3.30%

Last modified

CVE-2021-42911 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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.. EPSS estimates a 3.30% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
3.30%

87.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
DraytekVigor2960 Firmware<= 1.5.1.3
DraytekVigor3900 Firmware<= 1.5.1.3
DraytekVigor300b Firmware<= 1.5.1.3

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is 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.
How severe is CVE-2021-42911?
CVE-2021-42911 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 3.30% probability of exploitation in the next 30 days.
How do I fix CVE-2021-42911?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-42911?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST