CVE-2021-42911 is a critical Format String vulnerability affecting DrayTek Vigor 2960, 3900, and 300B routers running firmware versions up to 1.5.1.3. This flaw, residing in the mainfunction.cgi file, allows a remote, unauthenticated attacker to execute arbitrary code by sending a specially crafted HTTP message with a malformed query string. With a CVSS score of 9.8 (Critical), this vulnerability presents a severe risk due to its network-based attack vector, low attack complexity, and high impact on confidentiality, integrity, and availability. While no active exploitation or public exploit code (Metasploit, Nuclei, ExploitDB) has been identified, and community discussion is minimal, the potential for significant compromise necessitates immediate patching.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
<= 1.5.1.3CPE matchmatch criteria | cpe:2.3:o:draytek:vigor2960_firmware:*:*:*:*:*:*:*:* | ||
<= 1.5.1.3CPE matchmatch criteria | cpe:2.3:o:draytek:vigor3900_firmware:*:*:*:*:*:*:*:* | ||
<= 1.5.1.3CPE matchmatch criteria | cpe:2.3:o:draytek:vigor300b_firmware:*:*:*:*:*:*:*:* |
CVSS version used by this source: 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.
No media coverage found for this CVE.
The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.
Remediation records are not available for this CVE.