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Exploitation reportedNot in CISA KEV yet

CVE-2021-20039

Exploitation reported by one source. First attested on 2025-07-16 by GCVE · kevintel.

  • Published2021-12-08
  • WeaknessCWE-78

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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

dates in UTC
  1. 2021-12-0810:15CVE publishedNVD
  2. 2025-07-1617:25Listed as exploited by GCVEGCVE
  3. 2025-07-1617:25Exploitation first reportedGCVE

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-20039?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-20039?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Sonicwall sma 200 firmwareversion to verify
BranchAffectedFixed in
9.0= 9.0.0.11-31svno fix published
10.2= 10.2.0.8-37svno fix published
10.2= 10.2.1.1-19svno fix published
Sonicwall sma 210 firmwareversion to verify
BranchAffectedFixed in
9.0= 9.0.0.11-31svno fix published
10.2= 10.2.0.8-37svno fix published
10.2= 10.2.1.1-19svno fix published
Sonicwall sma 400 firmwareversion to verify
BranchAffectedFixed in
9.0= 9.0.0.11-31svno fix published
10.2= 10.2.0.8-37svno fix published
10.2= 10.2.1.1-19svno fix published

2 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As sonicwall, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • SonicWall SMA100
    Affected
    • = 9.0.0.11-31sv and earlierno fix stated
    • = 10.2.0.8-37sv and earlierno fix stated
    • = 10.2.1.1-19sv and earlierno fix stated
    • = 10.2.1.2-24sv and earlierno fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2022-01-13

Fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
1 moduleexploit/linux/http/sonicwall_cve_2021_20039rank: excellentModule metadata: Metasploit Framework, © Rapid7, Inc., BSD-3-Clause.
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
2021-12-08
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-58fc-493g-jfwj

Frequently asked questions

What is CVE-2021-20039?

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.

Is CVE-2021-20039 actively exploited?

A proof-of-concept exploit exists for CVE-2021-20039, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2021-20039?

CVE-2021-20039 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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Sources for this record