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Fencer Vulns
high 8.8

CVE-2021-20039 in the critical feed json

Improper neutralization of special elements in the SMA100 management interface '/cgi-bin/viewcert' POST http method allows a remote authent…

published 2021-12-08 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-7502

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
78.7%
EPSS 78.7% chance of exploitation in 30 days, percentile 99.5%
public exploits
1
Metasploit

Summary

Improper neutralization of special elements in the SMA100 management interface '/cgi-bin/viewcert' POST http method allows a remote authenticated attacker to inject arbitrary commands as a 'nobody' user. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances.

Timeline

  1. Published
  2. First public exploit (Metasploit exploit/linux/http/sonicwall_cve_2021_20039)

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
14 mo ago

Exploit prediction

78.75% chance of exploitation in the next 30 days, higher than 99.5% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • Metasploit exploit/linux/http/sonicwall_cve_2021_20039 SonicWall SMA 100 Series Authenticated Command Injection metasploit exploit, excellent rank, 2021-12-14
  • attackerkb.com https://attackerkb.com/topics/9szJhq46lw/cve-2021-20039/rapid7-analysis referenced PoC, tagged "exploit" by a source, unverified
  • packetstormsecurity.com http://packetstormsecurity.com/files/165563/SonicWall-SMA-100-Series-Authenticated-Command-Injection.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 9.0 AV:N/AC:L/Au:S/C:C/I:C/A:C

Affected products

  • SonicWall SonicWall SMA100

Classification

Weakness
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.