THREATPORT/VULNERABILITY/CVE-2021-42911
CRITICAL SEVERITY

CVE-2021-42911

Vigor2960 Firmware vulnerability

CVSS
9.8
EPSS
3.3%
EPSS pct
87th
Exploited
No known
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.
Affected vendor
Draytek
Affected product
Vigor2960 Firmware
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness type (CWE)
  • CWE-134 — Uncontrolled Format String
Published
2022-03-29

Risk analysis

Based on its CVSS vector, this vulnerability is exploitable over the network, low attack complexity, requiring no privileges, no user interaction. Successful exploitation leads to high impact to confidentiality, high impact to integrity, high impact to availability.

Its EPSS score of 3.3% reflects a lower probability of exploitation activity in the wild over the next 30 days, placing it above 87% of all scored CVEs.

Check your external exposure to CVE-2021-42911

  • Confirm whether Draytek Vigor2960 Firmware is running on any internet-facing host or subdomain.
  • Match discovered service fingerprints against the version affected by CVE-2021-42911.
  • Prioritise remediation if the asset is public, business-critical, or near authentication/payment flows.

How ThreatPort helps with CVE-2021-42911

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